- The Ethereal FAQ
+ The Wireshark FAQ
Note: This is just an ASCII snapshot of the faq and may not be up to
- date. Please go to http://www.ethereal.com/faq for the up to
- date version. The version of this snapshot can be found at the
- end of this document.
+ date. Please go to http://www.wireshark.org/faq.html for the up
+ to date version. The version of this snapshot can be found at
+ the end of this document.
INDEX
- General Questions:
- 1.1 Where can I get help?
+1. General Questions:
- 1.2 What protocols are currently supported?
+ 1.1 What is Wireshark?
- 1.3 Are there any plans to support {your favorite protocol}?
+ 1.2 What's up with the name change? Is Wireshark a fork?
- 1.4 Can Ethereal read capture files from {your favorite network
- analyzer}?
+ 1.3 Where can I get help?
+
+ 1.4 How much does Wireshark cost?
+
+ 1.5 Can I use Wireshark commercially?
+
+ 1.6 Can I use Wireshark as part of my commercial product?
+
+ 1.7 What protocols are currently supported?
- 1.5 What devices can Ethereal use to capture packets?
+ 1.8 Are there any plans to support {your favorite protocol}?
- 1.6 How do you pronounce Ethereal? Where did the name come from?
+ 1.9 Can Wireshark read capture files from {your favorite network analyzer}?
- Downloading Ethereal:
+ 1.10 What devices can Wireshark use to capture packets?
- 2.1 I downloaded the Win32 installer, but when I try to run it, I get
- an error.
+ 1.11 Does Wireshark work on Windows Me?
- 2.2 When I try to download the WinPcap driver and library, I can't get
- to the WinPcap Web site.
+ 1.12 Does Wireshark work on Windows XP?
- Installing Ethereal:
+2. Downloading Wireshark:
- 3.1 I installed an Ethereal RPM, but Ethereal doesn't seem to be
- installed; only Tethereal is installed.
+ 2.1 Why do I get an error when I try to run the Win32 installer?
- Building Ethereal:
+3. Installing Wireshark:
- 4.1 The configure script can't find pcap.h or bpf.h, but I have
- libpcap installed.
+ 3.1 I installed the Wireshark RPM (or other package); why did it install
+ TShark but not Wireshark?
+
+4. Building Wireshark:
+
+ 4.1 I have libpcap installed; why did the configure script not find pcap.h
+ or bpf.h?
4.2 Why do I get the error
- dftest_DEPENDENCIES was already defined in condition TRUE, which
- implies condition HAVE_PLUGINS_TRUE
+ dftest_DEPENDENCIES was already defined in condition TRUE, which implies
+ condition HAVE_PLUGINS_TRUE
- when I try to build Ethereal from CVS or a CVS snapshot?
+ when I try to build Wireshark from SVN or a SVN snapshot?
- 4.3 The link fails with a number of "Output line too long." messages
- followed by linker errors.
+ 4.3 Why does the linker fail with a number of "Output line too long."
+ messages followed by linker errors when I try to buil Wireshark?
- 4.4 The link fails on Solaris because plugin_list is undefined.
+ 4.4 When I try to build Wireshark on Solaris, why does the link fail
+ complaining that plugin_list is undefined?
- 4.5 The build fails on Windows because of conflicts between winsock.h
- and winsock2.h.
+ 4.5 When I try to build Wireshark on Windows, why does the build fail
+ because of conflicts between winsock.h and winsock2.h?
- Using Ethereal:
+5. Starting Wireshark:
- 5.1 When I use Ethereal to capture packets, I see only packets to and
- from my machine, or I'm not seeing all the traffic I'm expecting to
- see from or to the machine I'm trying to monitor.
+ 5.1 Why does Wireshark crash with a Bus Error when I try to run it on
+ Solaris 8?
- 5.2 I can't see any TCP packets other than packets to and from my
- machine, even though another sniffer on the network sees those
- packets.
+ 5.2 When I run Wireshark on Windows NT, why does it die with a Dr. Watson
+ error, reporting an "Integer division by zero" exception, when I start it?
- 5.3 I'm only seeing ARP packets when I try to capture traffic.
+ 5.3 When I try to run Wireshark, why does it complain about
+ sprint_realloc_objid being undefined?
- 5.4 How do I put an interface into promiscuous mode?
+ 5.4 When I try to run Wireshark on Windows, why does it fail to run with a
+ complaint that it can't find packet.dll?
- 5.5 I can set a display filter just fine, but capture filters don't
- work.
+ 5.5 I've installed Wireshark from Fink on Mac OS X; why is it very slow to
+ start up?
- 5.6 I'm entering valid capture filters, but I still get "parse error"
- errors.
+6. Crashes and other fatal errors:
- 5.7 I saved a filter and tried to use its name to filter the display,
- but I got an "Unexpected end of filter string" error.
+ 6.1 I have an XXX network card on my machine; if I try to capture on it, why
+ does my machine crash or reset itself?
- 5.8 Why am I seeing lots of packets with incorrect TCP checksums?
+ 6.2 Why does my machine crash or reset itself when I select "Start" from the
+ "Capture" menu or select "Preferences" from the "Edit" menu?
- 5.9 I've just installed Ethereal, and the traffic on my local LAN is
- boring.
+7. Capturing packets:
- 5.10 When I run Ethereal on Solaris 8, it dies with a Bus Error when I
- start it.
+ 7.1 When I use Wireshark to capture packets, why do I see only packets to
+ and from my machine, or not see all the traffic I'm expecting to see from or
+ to the machine I'm trying to monitor?
- 5.11 I'm running Ethereal on Linux; why do my time stamps have only
- 100ms resolution, rather than 1us resolution?
+ 7.2 When I capture with Wireshark, why can't I see any TCP packets other
+ than packets to and from my machine, even though another analyzer on the
+ network sees those packets?
+
+ 7.3 Why am I only seeing ARP packets when I try to capture traffic?
+
+ 7.4 Why am I not seeing any traffic when I try to capture traffic?
+
+ 7.5 Can Wireshark capture on (my T1/E1 line, SS7 links, etc.)?
+
+ 7.6 How do I put an interface into promiscuous mode?
+
+ 7.7 I can set a display filter just fine; why don't capture filters work?
+
+ 7.8 I'm entering valid capture filters; why do I still get "parse error"
+ errors?
+
+ 7.9 How can I capture packets with CRC errors?
+
+ 7.10 How can I capture entire frames, including the FCS?
+
+ 7.11 I'm capturing packets on a machine on a VLAN; why don't the packets I'm
+ capturing have VLAN tags?
+
+ 7.12 Why does Wireshark hang after I stop a capture?
- 5.12 I'm capturing packets on {Windows 95, Windows 98, Windows Me};
- why are the time stamps on packets wrong?
+8. Capturing packets on Windows:
- 5.13 When I try to run Ethereal on Windows, it fails to run because it
- can't find packet.dll.
+ 8.1 I'm running Wireshark on Windows; why does some network interface on my
+ machine not show up in the list of interfaces in the "Interface:" field in
+ the dialog box popped up by "Capture->Start", and/or why does Wireshark give
+ me an error if I try to capture on that interface?
- 5.14 Why does some network interface on my machine not show up in the
- list of interfaces in the "Interface:" field in the dialog box popped
- up by "Capture->Start", and/or why does Ethereal give me an error if I
- try to capture on that interface?
+ 8.2 I'm running Wireshark on Windows; why do no network interfaces show up
+ in the list of interfaces in the "Interface:" field in the dialog box popped
+ up by "Capture->Start"?
- 5.15 I'm running Ethereal on Windows NT/2000/XP/Server; my machine has
- a PPP (dial-up POTS, ISDN, etc.) interface, and it shows up in the
- "Interface" item in the "Capture Options" dialog box. Why can no
- packets be sent on or received from that network while I'm trying to
+ 8.3 I'm running Wireshark on Windows; why doesn't my serial port/ADSL
+ modem/ISDN modem show up in the list of interfaces in the "Interface:" field
+ in the dialog box popped up by "Capture->Start"?
+
+ 8.4 I'm running Wireshark on Windows NT 4.0/Windows 2000/Windows XP/Windows
+ Server 2003; my machine has a PPP (dial-up POTS, ISDN, etc.) interface, and
+ it shows up in the "Interface" item in the "Capture Options" dialog box. Why
+ can no packets be sent on or received from that network while I'm trying to
capture traffic on that interface?
- 5.16 I'm running Ethereal on Windows 95/98/Me, on a machine with more
- than one network adapter of the same type; Ethereal shows all of those
- adapters with the same name, but I can't use any of those adapters
- other than the first one.
-
- 5.17 I have an XXX network card on my machine; if I try to capture on
- it, my machine crashes or resets itself.
-
- 5.18 My machine crashes or resets itself when I select "Start" from
- the "Capture" menu or select "Preferences" from the "Edit" menu.
-
- 5.19 Does Ethereal work on Windows ME?
-
- 5.20 Does Ethereal work on Windows XP?
-
- 5.21 Why doesn't Ethereal correctly identify RTP packets? It shows
- them only as UDP.
-
- 5.22 Why doesn't Ethereal show Yahoo Messenger packets in captures
- that contain Yahoo Messenger traffic?
-
- 5.23 Why do I get the error
-
- Gdk-ERROR **: Palettized display (256-colour) mode not supported on
- Windows.
- aborting....
-
- when I try to run Ethereal on Windows?
-
- 5.24 When I capture on Windows in promiscuous mode, I can see packets
- other than those sent to or from my machine; however, those packets
- show up with a "Short Frame" indication, unlike packets to or from my
- machine. What should I do to arrange that I see those packets in their
- entirety?
-
- 5.25 How can I capture raw 802.11 packets, including non-data
- (management, beacon) packets?
-
- 5.26 How can I capture packets with CRC errors?
-
- 5.27 How can I capture entire frames, including the FCS?
-
- 5.28 Ethereal hangs after I stop a capture.
-
- 5.29 How can I search for, or filter, packets that have a particular
- string anywhere in them?
-
- GENERAL QUESTIONS
- Q 1.1: Where can I get help?
-
- A: Support is available on the ethereal-users mailing list.
- Subscription information and archives for all of Ethereal's mailing
- lists can be found at http://www.ethereal.com/lists
-
- Q 1.2: What protocols are currently supported?
-
- A: There are currently 366 supported protocols and media, listed
- below. Descriptions can be found in the ethereal(1) man page.
-
- 802.1q Virtual LAN
- 802.1x Authentication
- AFS (4.0) Replication Server call declarations
- AOL Instant Messenger
- ARCNET
- ATM
- ATM AAL1
- ATM AAL3/4
- ATM LAN Emulation
- ATM OAM AAL
- AVS WLAN Capture header
- Ad hoc On-demand Distance Vector Routing Protocol
- Ad hoc On-demand Distance Vector Routing Protocol v6
- Address Resolution Protocol
- Aggregate Server Access Protocol
- Andrew File System (AFS)
- Apache JServ Protocol v1.3
- AppleTalk Filing Protocol
- AppleTalk Session Protocol
- AppleTalk Transaction Protocol packet
- Appletalk Address Resolution Protocol
- Async data over ISDN (V.120)
- Authentication Header
- BACnet Virtual Link Control
- Banyan Vines
- Banyan Vines Fragmentation Protocol
- Banyan Vines SPP
- Blocks Extensible Exchange Protocol
- Boardwalk
- Boot Parameters
- Bootstrap Protocol
- Border Gateway Protocol
- Building Automation and Control Network APDU
- Building Automation and Control Network NPDU
- CDS Clerk Server Calls
- Check Point High Availability Protocol
- Checkpoint FW-1
- Cisco Auto-RP
- Cisco Discovery Protocol
- Cisco Group Management Protocol
- Cisco HDLC
- Cisco Hot Standby Router Protocol
- Cisco ISL
- Cisco Interior Gateway Routing Protocol
- Cisco NetFlow
- Cisco SLARP
- Clearcase NFS
- CoSine IPNOS L2 debug output
- Common Open Policy Service
- Common Unix Printing System (CUPS) Browsing Protocol
- DCE DFS Calls
- DCE Distributed Time Service Local Server
- DCE Distributed Time Service Provider
- DCE Name Service
- DCE RPC
- DCE Security ID Mapper
- DCE/RPC BOS Server
- DCE/RPC CDS Solicitation
- DCE/RPC Conversation Manager
- DCE/RPC Endpoint Mapper
- DCE/RPC FLDB
- DCE/RPC FLDB UBIK TRANSFER
- DCE/RPC FLDB UBIKVOTE
- DCE/RPC Kerberos V
- DCE/RPC RS_ACCT
- DCE/RPC RS_MISC
- DCE/RPC RS_UNIX
- DCE/RPC Remote Management
- DCE/RPC Repserver Calls
- DCE/RPC TokenServer Calls
- DCE/RPC UpServer
- DCOM OXID Resolver
- DCOM Remote Activation
- DEC Spanning Tree Protocol
- DHCPv6
- DNS Control Program Server
- Data
- Data Link SWitching
- Data Stream Interface
- Datagram Delivery Protocol
- Diameter Protocol
- Distance Vector Multicast Routing Protocol
- Distributed Checksum Clearinghouse Prototocl
- Domain Name Service
- Dynamic DNS Tools Protocol
- Encapsulating Security Payload
- Enhanced Interior Gateway Routing Protocol
- Ethernet
- Ethernet over IP
- Extensible Authentication Protocol
- FC Extended Link Svc
- FC Fabric Configuration Server
- FCIP
- FTP Data
- FTServer Operations
- Fiber Distributed Data Interface
- Fibre Channel
- Fibre Channel Common Transport
- Fibre Channel Fabric Zone Server
- Fibre Channel Name Server
- Fibre Channel Protocol for SCSI
- Fibre Channel SW_ILS
- File Transfer Protocol (FTP)
- Financial Information eXchange Protocol
- Frame
- Frame Relay
- GARP Multicast Registration Protocol
- GARP VLAN Registration Protocol
- GPRS Tunneling Protocol
- GPRS Tunnelling Protocol v0
- GPRS Tunnelling Protocol v1
- General Inter-ORB Protocol
- Generic Routing Encapsulation
- Generic Security Service Application Program Interface
- Gnutella Protocol
- HP Extended Local-Link Control
- HP Remote Maintenance Protocol
- Hummingbird NFS Daemon
- HyperSCSI
- Hypertext Transfer Protocol
- ICQ Protocol
- IEEE 802.11 wireless LAN
- IEEE 802.11 wireless LAN management frame
- ILMI
- IP Over FC
- IP Payload Compression
- IPX Message
- IPX Routing Information Protocol
- ISDN
- ISDN Q.921-User Adaptation Layer
- ISDN User Part
- ISO 10589 ISIS InTRA Domain Routeing Information Exchange Protocol
- ISO 8073 COTP Connection-Oriented Transport Protocol
- ISO 8473 CLNP ConnectionLess Network Protocol
- ISO 8602 CLTP ConnectionLess Transport Protocol
- ISO 9542 ESIS Routeing Information Exchange Protocol
- ITU-T Recommendation H.261
- Inter-Access-Point Protocol
- Interbase
- Internet Cache Protocol
- Internet Content Adaptation Protocol
- Internet Control Message Protocol
- Internet Control Message Protocol v6
- Internet Group Management Protocol
- Internet Message Access Protocol
- Internet Printing Protocol
- Internet Protocol
- Internet Protocol Version 6
- Internet Relay Chat
- Internet Security Association and Key Management Protocol
- Internetwork Packet eXchange
- Java RMI
- Java Serialization
- Kerberos
- Kernel Lock Manager
- Label Distribution Protocol
- Layer 2 Tunneling Protocol
- Lightweight Directory Access Protocol
- Line Printer Daemon Protocol
- Link Access Procedure Balanced (LAPB)
- Link Access Procedure Balanced Ethernet (LAPBETHER)
- Link Access Procedure, Channel D (LAPD)
- Link Aggregation Control Protocol
- Link Management Protocol (LMP)
- Linux cooked-mode capture
- Local Management Interface
- LocalTalk Link Access Protocol
- Logical-Link Control
- Lucent/Ascend debug output
- MDS Header
- MMS Message Encapsulation
- MS Proxy Protocol
- MSN Messenger Service
- MSNIP: Multicast Source Notification of Interest Protocol
- MTP 2 Transparent Proxy
- MTP 2 User Adaptation Layer
- MTP 3 User Adaptation Layer
- MTP2 Peer Adaptation Layer
- Message Transfer Part Level 2
- Message Transfer Part Level 3
- Message Transfer Part Level 3 Management
- Microsoft Distributed File System
- Microsoft Exchange MAPI
- Microsoft Local Security Architecture
- Microsoft Local Security Architecture (Directory Services)
- Microsoft Network Logon
- Microsoft Registry
- Microsoft Security Account Manager
- Microsoft Server Service
- Microsoft Spool Subsystem
- Microsoft Telephony API Service
- Microsoft Windows Browser Protocol
- Microsoft Windows Lanman Remote API Protocol
- Microsoft Windows Logon Protocol
- Microsoft Workstation Service
- Mobile IP
- Mobile IPv6
- Modbus/TCP
- Mount Service
- MultiProtocol Label Switching Header
- Multicast Router DISCovery protocol
- Multicast Source Discovery Protocol
- MySQL Protocol
- NFSACL
- NFSAUTH
- NIS+
- NIS+ Callback
- NSPI
- NTLM Secure Service Provider
- Name Binding Protocol
- Name Management Protocol over IPX
- NetBIOS
- NetBIOS Datagram Service
- NetBIOS Name Service
- NetBIOS Session Service
- NetBIOS over IPX
- NetWare Core Protocol
- Network Data Management Protocol
- Network File System
- Network Lock Manager Protocol
- Network News Transfer Protocol
- Network Status Monitor CallBack Protocol
- Network Status Monitor Protocol
- Network Time Protocol
- Novell Distributed Print System
- Null/Loopback
- Open Shortest Path First
- OpenBSD Encapsulating device
- OpenBSD Packet Filter log file
- PC NFS
- PPP Bandwidth Allocation Control Protocol
- PPP Bandwidth Allocation Protocol
- PPP CDP Control Protocol
- PPP Callback Control Protocol
- PPP Challenge Handshake Authentication Protocol
- PPP Compressed Datagram
- PPP Compression Control Protocol
- PPP IP Control Protocol
- PPP IPv6 Control Protocol
- PPP Link Control Protocol
- PPP MPLS Control Protocol
- PPP Multilink Protocol
- PPP Multiplexing
- PPP Password Authentication Protocol
- PPP VJ Compression
- PPP-over-Ethernet Discovery
- PPP-over-Ethernet Session
- PPPMux Control Protocol
- Point-to-Point Protocol
- Point-to-Point Tunnelling Protocol
- Portmap
- Post Office Protocol
- Pragmatic General Multicast
- Prism
- Privilege Server operations
- Protocol Independent Multicast
- Q.2931
- Q.931
- Quake II Network Protocol
- Quake III Arena Network Protocol
- Quake Network Protocol
- QuakeWorld Network Protocol
- Qualified Logical Link Control
- RFC 2250 MPEG1
- RIPng
- RPC Browser
- RSTAT
- RSYNC File Synchroniser
- RX Protocol
- Radio Access Network Application Part
- Radius Protocol
- Raw packet data
- Real Time Streaming Protocol
- Real-Time Transport Protocol
- Real-time Transport Control Protocol
- Registry Server Attributes Manipulation Interface
- Registry server administration operations.
- Remote Override interface
- Remote Procedure Call
- Remote Program Load
- Remote Quota
- Remote Shell
- Remote Wall protocol
- Remote sec_login preauth interface.
- Resource ReserVation Protocol (RSVP)
- Rlogin Protocol
- Routing Information Protocol
- Routing Table Maintenance Protocol
- SADMIND
- SCSI
- SGI Mount Service
- SMB (Server Message Block Protocol)
- SMB MailSlot Protocol
- SMB Pipe Protocol
- SNA-over-Ethernet
- SNMP Multiplex Protocol
- SPNEGO-KRB5
- SPRAY
- SS7 SCCP-User Adaptation Layer
- SSCOP
- SSH Protocol
- Secure Socket Layer
- Sequenced Packet eXchange
- Service Advertisement Protocol
- Service Location Protocol
- Session Announcement Protocol
- Session Description Protocol
- Session Initiation Protocol
- Short Message Peer to Peer
- Signalling Connection Control Part
- Signalling Connection Control Part Management
- Simple Mail Transfer Protocol
- Simple Network Management Protocol
- Sinec H1 Protocol
- Skinny Client Control Protocol
- SliMP3 Communication Protocol
- Socks Protocol
- Spanning Tree Protocol
- Spnego
- Stream Control Transmission Protocol
- Synchronous Data Link Control (SDLC)
- Syslog message
- Systems Network Architecture
- Systems Network Architecture XID
- TACACS
- TACACS+
- TPKT
- Tabular Data Stream
- Tazmen Sniffer Protocol
- Telnet
- Time Protocol
- Time Synchronization Protocol
- Token-Ring
- Token-Ring Media Access Control
- Transmission Control Protocol
- Transparent Network Substrate Protocol
- Trivial File Transfer Protocol
- Universal Computer Protocol
- User Datagram Protocol
- Virtual Router Redundancy Protocol
- Virtual Trunking Protocol
- WAP Binary XML
- Web Cache Coordination Protocol
- Wellfleet Breath of Life
- Wellfleet Compression
- Wellfleet HDLC
- Who
- Windows 2000 DNS
- Wireless Session Protocol
- Wireless Transaction Protocol
- Wireless Transport Layer Security
- X Display Manager Control Protocol
- X.25
- X.25 over TCP
- X.29
- X11
- Xyplex
- Yahoo Messenger Protocol
- Yahoo YMSG Messenger Protocol
- Yellow Pages Bind
- Yellow Pages Passwd
- Yellow Pages Service
- Yellow Pages Transfer
- Zebra Protocol
- Zone Information Protocol
- iSCSI
-
- Q 1.3: Are there any plans to support {your favorite protocol}?
-
- A: Support for particular protocols is added to Ethereal as a result
- of people contributing that support; no formal plans for adding
- support for particular protocols in particular future releases exist.
-
- Q 1.4: Can Ethereal read capture files from {your favorite network
+ 8.5 I'm running Wireshark on Windows 95/98/Me, on a machine with more than
+ one network adapter of the same type; why does Wireshark show all of those
+ adapters with the same name, not letting me use any of those adapters other
+ than the first one?
+
+ 8.6 I'm running Wireshark on Windows; why am I not seeing any traffic being
+ sent by the machine running Wireshark?
+
+ 8.7 When I capture on Windows in promiscuous mode, I can see packets other
+ than those sent to or from my machine; however, those packets show up with a
+ "Short Frame" indication, unlike packets to or from my machine. What should
+ I do to arrange that I see those packets in their entirety?
+
+ 8.8 I'm capturing packets on {Windows 95, Windows 98, Windows Me}; why are
+ the time stamps on packets wrong?
+
+ 8.9 I'm trying to capture 802.11 traffic on Windows; why am I not seeing any
+ packets?
+
+ 8.10 I'm trying to capture 802.11 traffic on Windows; why am I seeing
+ packets received by the machine on which I'm capturing traffic, but not
+ packets sent by that machine?
+
+ 8.11 I'm trying to capture Ethernet VLAN traffic on Windows, and I'm
+ capturing on a "raw" Ethernet device rather than a "VLAN interface", so that
+ I can see the VLAN headers; why am I seeing packets received by the machine
+ on which I'm capturing traffic, but not packets sent by that machine?
+
+9. Capturing packets on UN*Xes:
+
+ 9.1 I'm running Wireshark on a UNIX-flavored OS; why does some network
+ interface on my machine not show up in the list of interfaces in the
+ "Interface:" field in the dialog box popped up by "Capture->Start", and/or
+ why does Wireshark give me an error if I try to capture on that interface?
+
+ 9.2 I'm running Wireshark on a UNIX-flavored OS; why do no network
+ interfaces show up in the list of interfaces in the "Interface:" field in
+ the dialog box popped up by "Capture->Start"?
+
+ 9.3 I'm capturing packets on Linux; why do the time stamps have only 100ms
+ resolution, rather than 1us resolution?
+
+10. Capturing packets on wireless LANs:
+
+ 10.1 How can I capture raw 802.11 frames, including non-data (management,
+ beacon) frames?
+
+ 10.2 How do I capture on an 802.11 device in monitor mode?
+
+11. Viewing traffic:
+
+ 11.1 Why am I seeing lots of packets with incorrect TCP checksums?
+
+ 11.2 I've just installed Wireshark, and the traffic on my local LAN is
+ boring. Where can I find more interesting captures?
+
+ 11.3 Why doesn't Wireshark correctly identify RTP packets? It shows them
+ only as UDP.
+
+ 11.4 Why doesn't Wireshark show Yahoo Messenger packets in captures that
+ contain Yahoo Messenger traffic?
+
+12. Filtering traffic:
+
+ 12.1 I saved a filter and tried to use its name to filter the display; why
+ do I get an "Unexpected end of filter string" error?
+
+ 12.2 How can I search for, or filter, packets that have a particular string
+ anywhere in them?
+
+ 12.3 How do I filter a capture to see traffic for virus XXX?
+
+1. General Questions
+
+ Q 1.1: What is Wireshark?
+
+ A: Gerald Combs, the creator of Ethereal®, has initiated the Wireshark
+ network protocol analyzer project, a successor to Ethereal®. The Ethereal®
+ core developer team has moved with Gerald to the Wireshark project. It is
+ the world's most popular network protocol analyzer. It has a rich and
+ powerful feature set, and runs on most computing platforms including
+ Windows, OS X, and Linux. It is freely available as open source, and is
+ released under the GNU General Public License.
+
+ For more information, please see the About Wireshark page.
+
+ Q 1.2: What's up with the name change? Is Wireshark a fork?
+
+ A: In May of 2006, the original author of Ethereal® went to work for CACE
+ Technologies (best known for WinPcap). Unfortunately, he had to leave the
+ Ethereal® trademarks behind.
+
+ This left the project in an awkward position. The only reasonable way to
+ ensure the continued success of the project was to change the name. This is
+ how Wireshark was born.
+
+ Wireshark is almost (but not quite) a fork. Normally a "fork" of an open
+ source project results in two names, web sites, development teams, support
+ infrastructures, etc. This is the case with Wireshark except for one notable
+ exception -- every member of the core development team is now working on
+ Wireshark. More information on the name change can be found here:
+ *
+ *
+
+ Q 1.3: Where can I get help?
+
+ A: Community support is available on the wireshark-users mailing list.
+ Subscription information and archives for all of Wireshark's mailing lists
+ can be found at http://www.wireshark.org/mailman/listinfo. An IRC channel
+ dedicated to Wireshark can be found at irc://irc.freenode.net/wireshark.
+
+ Commercial support, training, and development services are available from
+ CACE Technologies.
+
+ Q 1.4: How much does Wireshark cost?
+
+ A: Wireshark is "free software"; you can download it without paying any
+ license fee. The version of Wireshark you download isn't a "demo" version,
+ with limitations not present in a "full" version; it is the full version.
+
+ The license under which Wireshark is issued is the GNU General Public
+ License. See the GNU GPL FAQ for some more information.
+
+ Q 1.5: Can I use Wireshark commercially?
+
+ A: Yes, if, for example, you mean "I work for a commercial organization; can
+ I use Wireshark to capture and analyze network traffic in our company's
+ networks or in our customer's networks?"
+
+ If you mean "Can I use Wireshark as part of my commercial product?", see the
+ next entry in the FAQ.
+
+ Q 1.6: Can I use Wireshark as part of my commercial product?
+
+ A: As noted, Wireshark is licensed under the GNU General Public License. The
+ GPL imposes conditions on your use of GPL'ed code in your own products; you
+ cannot, for example, make a "derived work" from Wireshark, by making
+ modifications to it, and then sell the resulting derived work and not allow
+ recipients to give away the resulting work. You must also make the changes
+ you've made to the Wireshark source available to all recipients of your
+ modified version; those changes must also be licensed under the terms of the
+ GPL. See the GPL FAQ for more details; in particular, note the answer to the
+ question about modifying a GPLed program and selling it commercially, and
+ the question about linking GPLed code with other code to make a proprietary
+ program.
+
+ You can combine a GPLed program such as Wireshark and a commercial program
+ as long as they communicate "at arm's length", as per this item in the GPL
+ FAQ.
+
+ Q 1.7: What protocols are currently supported?
+
+ A: There are currently hundreds of supported protocols and media. Details
+ can be found in the wireshark(1) man page.
+
+ Q 1.8: Are there any plans to support {your favorite protocol}?
+
+ A: Support for particular protocols is added to Wireshark as a result of
+ people contributing that support; no formal plans for adding support for
+ particular protocols in particular future releases exist.
+
+ Q 1.9: Can Wireshark read capture files from {your favorite network
analyzer}?
- A: Support for particular protocols is added to Ethereal as a result
- of people contributing that support; no formal plans for adding
- support for particular protocols in particular future releases exist.
+ A: Support for particular protocols is added to Wireshark as a result of
+ people contributing that support; no formal plans for adding support for
+ particular protocols in particular future releases exist.
- If a network analyzer writes out files in a format already supported
- by Ethereal (e.g., in libpcap format), Ethereal may already be able to
- read them, unless the analyzer has added its own proprietary
- extensions to that format.
+ If a network analyzer writes out files in a format already supported by
+ Wireshark (e.g., in libpcap format), Wireshark may already be able to read
+ them, unless the analyzer has added its own proprietary extensions to that
+ format.
If a network analyzer writes out files in its own format, or has added
- proprietary extensions to another format, in order to make Ethereal
- read captures from that network analyzer, we would either have to have
- a specification for the file format, or the extensions, sufficient to
- give us enough information to read the parts of the file relevant to
- Ethereal, or would need at least one capture file in that format AND a
- detailed textual analysis of the packets in that capture file (showing
- packet time stamps, packet lengths, and the top-level packet header)
- in order to reverse-engineer the file format.
-
- Note that there is no guarantee that we will be able to
- reverse-engineer a capture file format.
-
- Q 1.5: What devices can Ethereal use to capture packets?
-
- A: Ethereal can read live data from Ethernet, Token-Ring, FDDI, serial
- (PPP and SLIP) (if the OS on which it's running allows Ethereal to do
- so), 802.11 wireless LAN (if the OS on which it's running allows
- Ethereal to do so), ATM connections (if the OS on which it's running
- allows Ethereal to do so), and the "any" device supported on Linux by
- recent versions of libpcap. See the list of supported capture media on
- various OSes for details (several items in there say "Unknown", which
- doesn't mean "Ethereal can't capture on them", it means "we don't know
- whether it can capture on them"; we expect that it will be able to
- capture on many of them, but we haven't tried it ourselves - if you
- try one of those types and it works, please send an update to
- ethereal-web[AT]ethereal.com).
+ proprietary extensions to another format, in order to make Wireshark read
+ captures from that network analyzer, we would either have to have a
+ specification for the file format, or the extensions, sufficient to give us
+ enough information to read the parts of the file relevant to Wireshark, or
+ would need at least one capture file in that format AND a detailed textual
+ analysis of the packets in that capture file (showing packet time stamps,
+ packet lengths, and the top-level packet header) in order to
+ reverse-engineer the file format.
+
+ Note that there is no guarantee that we will be able to reverse-engineer a
+ capture file format.
+
+ Q 1.10: What devices can Wireshark use to capture packets?
+
+ A: Wireshark can read live data from Ethernet, Token-Ring, FDDI, serial (PPP
+ and SLIP) (if the OS on which it's running allows Wireshark to do so),
+ 802.11 wireless LAN (if the OS on which it's running allows Wireshark to do
+ so), ATM connections (if the OS on which it's running allows Wireshark to do
+ so), and the "any" device supported on Linux by recent versions of libpcap.
It can also read a variety of capture file formats, including:
- * libpcap/tcpdump
- * Sun snoop/atmsnoop
- * Shomiti/Finisar Surveyor
- * LanAlyzer
- * DOS-based Sniffer (compressed and uncompressed)
- * MS Network Monitor
- * AIX iptrace
- * NetXray and Windows-based Sniffer
- * EtherPeek/TokenPeek/AiroPeek
- * RADCOM WAN/LAN analyzer
- * Lucent/Ascend debug output
- * Toshiba ISDN router "snoop" output
- * HPUX nettl
- * ISDN4BSD "i4btrace" utility.
- * Cisco Secure IDS
- * pppd log files (pppdump format)
- * VMS TCPIPtrace
- * DBS Etherwatch
- * Visual Networks' Visual UpTime
- * CoSine L2 debug
-
- so that it can read traces from various network types, as captured by
- other applications or equipment, even if it cannot itself capture on
- those network types.
-
- Q 1.6: How do you pronounce Ethereal? Where did the name come from?
-
- A: The English pronunciation can be found in Merriam-Webster's online
- dictionary at
- http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=ethereal.
-
- According to the book "Computer Networks" by Andrew Tannenbaum,
- Ethernet was named after the "luminiferous ether" which was once
- thought to carry electromagnetic radiation. Taking that into
- consideration, Ethereal seemed like an appropriate name for an
- Ethernet sniffer.
-
- DOWNLOADING ETHEREAL
- Q 2.1: I downloaded the Win32 installer, but when I try to run it, I
- get an error.
-
- A: The program you used to download it may have downloaded it
- incorrectly. Web browsers sometimes may do this.
+ * AG Group/WildPackets EtherPeek/TokenPeek/AiroPeek/EtherHelp/Packet
+ Grabber captures
+ * AIX's iptrace captures
+ * Accellent's 5Views LAN agent output
+ * Cinco Networks NetXRay captures
+ * Cisco Secure Intrusion Detection System IPLog output
+ * CoSine L2 debug output
+ * DBS Etherwatch VMS text output
+ * Endace Measurement Systems' ERF format captures
+ * EyeSDN USB S0 traces
+ * HP-UX nettl captures
+ * ISDN4BSD project i4btrace captures
+ * Linux Bluez Bluetooth stack hcidump -w traces
+ * Lucent/Ascend router debug output
+ * Microsoft Network Monitor captures
+ * Network Associates Windows-based Sniffer captures
+ * Network General/Network Associates DOS-based Sniffer (compressed or
+ uncompressed) captures
+ * Network Instruments Observer version 9 captures
+ * Novell LANalyzer captures
+ * RADCOM's WAN/LAN analyzer captures
+ * Shomiti/Finisar Surveyor captures
+ * Toshiba's ISDN routers dump output
+ * VMS TCPIPtrace/TCPtrace/UCX$TRACE output
+ * Visual Networks' Visual UpTime traffic capture
+ * libpcap, tcpdump and various other tools using tcpdump's capture format
+ * snoop and atmsnoop output
+
+ so that it can read traces from various network types, as captured by other
+ applications or equipment, even if it cannot itself capture on those network
+ types.
+
+ Q 1.11: Does Wireshark work on Windows Me?
+
+ A: Yes, but if you want to capture packets, you will need to install the
+ latest version of WinPcap, as 2.02 and earlier versions of WinPcap didn't
+ support Windows Me. You should also install the latest version of Wireshark
+ as well.
+
+ Q 1.12: Does Wireshark work on Windows XP?
+
+ A: Yes, but if you want to capture packets, you will need to install the
+ latest version of WinPcap, as 2.2 and earlier versions of WinPcap didn't
+ support Windows XP.
+
+2. Downloading Wireshark
+
+ Q 2.1: Why do I get an error when I try to run the Win32 installer?
+
+ A: The program you used to download it may have downloaded it incorrectly.
+ Web browsers sometimes may do this.
Try downloading it with, for example:
- * Wget, for which Windows binaries are available on the SunSITE FTP
- server at sunsite.tk or Heiko Herold's windows wget spot - wGetGUI
- offers a GUI interface that uses wget;
+ * Wget, for which Windows binaries are available on the SunSITE FTP server
+ at sunsite.tk or Heiko Herold's windows wget spot - wGetGUI offers a GUI
+ interface that uses wget;
* WS_FTP from Ipswitch,
* the ftp command that comes with Windows.
- If you use the ftp command, make sure you do the transfer in binary
- mode rather than ASCII mode, by using the binary command before
- transferring the file.
-
- Q 2.2: When I try to download the WinPcap driver and library, I can't
- get to the WinPcap Web site.
-
- A: As is the case with all Web sites, that site won't necessarily
- always be accessible; the server may be down due to a problem or down
- for maintenance, or there may be a networking problem between you and
- the server. You should try again later, or try the local mirror or the
- Wiretapped.net mirror.
-
- INSTALLING ETHEREAL
- Q 3.1: I installed an Ethereal RPM, but Ethereal doesn't seem to be
- installed; only Tethereal is installed.
-
- A: Red Hat RPMs for Ethereal put only the non-GUI components into the
- ethereal RPM, the fact that Ethereal is a GUI program nonwithstanding;
- there's a separate ethereal-gnome RPM that includes GUI components
- such as Ethereal itself, the fact that Ethereal doesn't use GNOME
- nonwithstanding. Find the ethereal-gnome RPM, and install that also.
-
- BUILDING ETHEREAL
- Q 4.1: The configure script can't find pcap.h or bpf.h, but I have
- libpcap installed.
-
- A: Are you sure pcap.h and bpf.h are installed? The official
- distribution of libpcap only installs the libpcap.a library file when
- "make install" is run. To install pcap.h and bpf.h, you must run "make
- install-incl". If you're running Debian or Redhat, make sure you have
- the "libpcap-dev" or "libpcap-devel" packages installed.
-
- It's also possible that pcap.h and bpf.h have been installed in a
- strange location. If this is the case, you may have to tweak
- aclocal.m4.
-
- Q 4.2: Why do I get the error
-
- dftest_DEPENDENCIES was already defined in condition TRUE, which
- implies condition HAVE_PLUGINS_TRUE
-
- when I try to build Ethereal from CVS or a CVS snapshot?
-
- A: You probably have automake 1.5 installed on your machine (the
- command automake --version will report the version of automake on your
- machine). There is a bug in that version of automake that causes this
- problem; upgrade to a later version of automake (1.6 or later).
-
- Q 4.3: The link fails with a number of "Output line too long."
- messages followed by linker errors.
-
- A: The version of the sed command on your system is incapable of
- handling very long lines. On Solaris, for example, /usr/bin/sed has a
- line length limit too low to allow libtool to work; /usr/xpg4/bin/sed
- can handle it, as can GNU sed if you have it installed.
-
- On Solaris, changing your command search path to search /usr/xpg4/bin
- before /usr/bin should make the problem go away; on any platform on
- which you have this problem, installing GNU sed and changing your
- command path to search the directory in which it is installed before
- searching the directory with the version of sed that came with the OS
- should make the problem go away.
-
- Q 4.4: The link fails on Solaris because plugin_list is undefined.
-
- A: This appears to be due to a problem with some versions of the GTK+
- and GLib packages from www.sunfreeware.org; un-install those packages,
- and try getting the 1.2.10 versions from that site, or the versions
- from The Written Word, or the versions from Sun's GNOME distribution,
- or the versions from the supplemental software CD that comes with the
- Solaris media kit, or build them from source from the GTK Web site.
- Then re-run the configuration script, and try rebuilding Ethereal. (If
- you get the 1.2.10 versions from www.sunfreeware.org, and the problem
- persists, un-install them and try installing one of the other versions
- mentioned.)
-
- Q 4.5: The build fails on Windows because of conflicts between
- winsock.h and winsock2.h.
-
- A: As of Ethereal 0.9.5, you must install WinPcap 2.3 or later, and
- the corresponding version of the developer's pack, in order to be able
- to compile Ethereal; it will not compile with older versions of the
+ If you use the ftp command, make sure you do the transfer in binary mode
+ rather than ASCII mode, by using the binary command before transferring the
+ file.
+
+3. Installing Wireshark
+
+ Q 3.1: I installed the Wireshark RPM (or other package); why did it install
+ TShark but not Wireshark?
+
+ A: Many distributions have separate Wireshark packages, one for non-GUI
+ components such as TShark, editcap, dumpcap, etc. and one for the GUI. If
+ this is the case on your system, there's probably a separate package named
+ wireshark-gnome or wireshark-gtk+. Find it and install it.
+
+4. Building Wireshark
+
+ Q 4.1: I have libpcap installed; why did the configure script not find
+ pcap.h or bpf.h?
+
+ A: Are you sure pcap.h and bpf.h are installed? The official distribution of
+ libpcap only installs the libpcap.a library file when "make install" is run.
+ To install pcap.h and bpf.h, you must run "make install-incl". If you're
+ running Debian or Redhat, make sure you have the "libpcap-dev" or
+ "libpcap-devel" packages installed.
+
+ It's also possible that pcap.h and bpf.h have been installed in a strange
+ location. If this is the case, you may have to tweak aclocal.m4.
+
+ Q 4.2: Why do I get the error
+
+ dftest_DEPENDENCIES was already defined in condition TRUE, which implies
+ condition HAVE_PLUGINS_TRUE
+
+ when I try to build Wireshark from SVN or a SVN snapshot?
+
+ A: You probably have automake 1.5 installed on your machine (the command
+ automake --version will report the version of automake on your machine).
+ There is a bug in that version of automake that causes this problem; upgrade
+ to a later version of automake (1.6 or later).
+
+ Q 4.3: Why does the linker fail with a number of "Output line too long."
+ messages followed by linker errors when I try to buil Wireshark?
+
+ A: The version of the sed command on your system is incapable of handling
+ very long lines. On Solaris, for example, /usr/bin/sed has a line length
+ limit too low to allow libtool to work; /usr/xpg4/bin/sed can handle it, as
+ can GNU sed if you have it installed.
+
+ On Solaris, changing your command search path to search /usr/xpg4/bin before
+ /usr/bin should make the problem go away; on any platform on which you have
+ this problem, installing GNU sed and changing your command path to search
+ the directory in which it is installed before searching the directory with
+ the version of sed that came with the OS should make the problem go away.
+
+ Q 4.4: When I try to build Wireshark on Solaris, why does the link fail
+ complaining that plugin_list is undefined?
+
+ A: This appears to be due to a problem with some versions of the GTK+ and
+ GLib packages from www.sunfreeware.org; un-install those packages, and try
+ getting the 1.2.10 versions from that site, or the versions from The Written
+ Word, or the versions from Sun's GNOME distribution, or the versions from
+ the supplemental software CD that comes with the Solaris media kit, or build
+ them from source from the GTK Web site. Then re-run the configuration
+ script, and try rebuilding Wireshark. (If you get the 1.2.10 versions from
+ www.sunfreeware.org, and the problem persists, un-install them and try
+ installing one of the other versions mentioned.)
+
+ Q 4.5: When I try to build Wireshark on Windows, why does the build fail
+ because of conflicts between winsock.h and winsock2.h?
+
+ A: As of Wireshark 0.9.5, you must install WinPcap 2.3 or later, and the
+ corresponding version of the developer's pack, in order to be able to
+ compile Wireshark; it will not compile with older versions of the
developer's pack. The symptoms of this failure are conflicts between
- definitions in winsock.h and in winsock2.h; Ethereal uses winsock2.h,
- but pre-2.3 versions of the WinPcap developer's packet use winsock.h.
- (2.3 uses winsock2.h, so if Ethereal were to use winsock.h, it would
- not be able to build with current versions of the WinPcap developer's
- pack.)
-
- Note that the installed version of the developer's pack should be the
- same version as the version of WinPcap you have installed.
-
- USING ETHEREAL
- Q 5.1: When I use Ethereal to capture packets, I see only packets to
- and from my machine, or I'm not seeing all the traffic I'm expecting
- to see from or to the machine I'm trying to monitor.
-
- A: This might be because the interface on which you're capturing is
- plugged into a switch; on a switched network, unicast traffic between
- two ports will not necessarily appear on other ports - only broadcast
- and multicast traffic will be sent to all ports.
-
- Note that even if your machine is plugged into a hub, the "hub" may be
- a switched hub, in which case you're still on a switched network.
-
- Note also that on the Linksys Web site, they say that their
- auto-sensing hubs "broadcast the 10Mb packets to the port that operate
- at 10Mb only and broadcast the 100Mb packets to the ports that operate
- at 100Mb only", which would indicate that if you sniff on a 10Mb port,
- you will not see traffic coming sent to a 100Mb port, and vice versa.
- This problem has also been reported for Netgear dual-speed hubs, and
- may exist for other "auto-sensing" or "dual-speed" hubs.
-
- Some switches have the ability to replicate all traffic on all ports
- to a single port so that you can plug your sniffer into that single
- port to sniff all traffic. You would have to check the documentation
- for the switch to see if this is possible and, if so, to see how to do
- this. See, for example:
- * this documentation from Cisco on the Switched Port Analyzer (SPAN)
- feature on Catalyst switches;
- * documentation from HP on how to set "monitoring"/"mirroring" on
- ports on the console for HP Advancestack Switch 208 and 224;
- * the "Network Monitoring Port Features" section of chapter 6 of
- documentation from HP for HP ProCurve Switches 1600M, 2424M,
- 4000M, and 8000M.
-
- Note also that many firewall/NAT boxes have a switch built into them;
- this includes many of the "cable/DSL router" boxes. If you have a box
- of that sort, that has a switch with some number of Ethernet ports
- into which you plug machines on your network, and another Ethernet
- port used to connect to a cable or DSL modem, you can, at least, sniff
- traffic between the machines on your network and the Internet by
- plugging the Ethernet port on the router going to the modem, the
- Ethernet port on the modem, and the machine on which you're running
- Ethereal into a hub (make sure it's not a switching hub, and that, if
- it's a dual-speed hub, all three of those ports are running at the
+ definitions in winsock.h and in winsock2.h; Wireshark uses winsock2.h, but
+ pre-2.3 versions of the WinPcap developer's packet use winsock.h. (2.3 uses
+ winsock2.h, so if Wireshark were to use winsock.h, it would not be able to
+ build with current versions of the WinPcap developer's pack.)
+
+ Note that the installed version of the developer's pack should be the same
+ version as the version of WinPcap you have installed.
+
+5. Starting Wireshark
+
+ Q 5.1: Why does Wireshark crash with a Bus Error when I try to run it on
+ Solaris 8?
+
+ A: Some versions of the GTK+ library from www.sunfreeware.org appear to be
+ buggy, causing Wireshark to drop core with a Bus Error. Un-install those
+ packages, and try getting the 1.2.10 version from that site, or the version
+ from The Written Word, or the version from Sun's GNOME distribution, or the
+ version from the supplemental software CD that comes with the Solaris media
+ kit, or build it from source from the GTK Web site. Update the GLib library
+ to the 1.2.10 version, from the same source, as well. (If you get the 1.2.10
+ versions from www.sunfreeware.org, and the problem persists, un-install them
+ and try installing one of the other versions mentioned.)
+
+ Similar problems may exist with older versions of GTK+ for earlier versions
+ of Solaris.
+
+ Q 5.2: When I run Wireshark on Windows NT, why does it die with a Dr. Watson
+ error, reporting an "Integer division by zero" exception, when I start it?
+
+ A: In at least some case, this appears to be due to using the default VGA
+ driver; if that's not the correct driver for your video card, try running
+ the correct driver for your video card.
+
+ Q 5.3: When I try to run Wireshark, why does it complain about
+ sprint_realloc_objid being undefined?
+
+ A: Wireshark can only be linked with version 4.2.2 or later of UCD SNMP.
+ Your version of Wireshark was dynamically linked with such a version of UCD
+ SNMP; however, you have an older version of UCD SNMP installed, which means
+ that when Wireshark is run, it tries to link to the older version, and
+ fails. You will have to replace that version of UCD SNMP with version 4.2.2
+ or a later version.
+
+ Q 5.4: When I try to run Wireshark on Windows, why does it fail to run with
+ a complaint that it can't find packet.dll?
+
+ A: In older versions of Wireshark, there were two binary distributions
+ available for Windows, one that supported capturing packets, and one that
+ didn't. The version that supported capturing packets required that you
+ install the WinPcap driver; if you didn't install it, it would fail to run
+ because it couldn't find packet.dll.
+
+ The current version of Wireshark has only one binary distribution for
+ Windows; that version will check whether WinPcap is installed and, if it's
+ not, will disable support for packet capture.
+
+ The WinPcap driver and libraries can be downloaded from the WinPcap Web site
+ or the Wiretapped.net mirror of the WinPcap site.
+
+ Q 5.5: I've installed Wireshark from Fink on Mac OS X; why is it very slow
+ to start up?
+
+ A: When an application is installed on OS X, prior to 10.4, it is usually
+ "prebound" to speed up launching the application. (That's what the
+ "Optimizing" phase of installation is.) Fink normally performs prebinding
+ automatically when you install a package. However, in some rare cases, for
+ whatever reason the prebinding caches get corrupt, and then not only does
+ prebinding fail, but startup actually becomes much slower, because the
+ system tries in vain to perform prebinding "on the fly" as you launch the
+ application. This fails, causing sometimes huge delays. To fix the
+ prebinding caches, run the command
+ sudo /sw/var/lib/fink/prebound/update-package-prebinding.pl -f
+
+6. Crashes and other fatal errors
+
+ Q 6.1: I have an XXX network card on my machine; if I try to capture on it,
+ why does my machine crash or reset itself?
+
+ A: This is almost certainly a problem with one or more of:
+ * the operating system you're using;
+ * the device driver for the interface you're using;
+ * the libpcap/WinPcap library and, if this is Windows, the WinPcap device
+ driver;
+
+ so:
+ * if you are using Windows, see the WinPcap support page - check the
+ "Submitting bugs" section;
+ * if you are using some Linux distribution, some version of BSD, or some
+ other UNIX-flavored OS, you should report the problem to the company or
+ organization that produces the OS (in the case of a Linux distribution,
+ report the problem to whoever produces the distribution).
+
+ Q 6.2: Why does my machine crash or reset itself when I select "Start" from
+ the "Capture" menu or select "Preferences" from the "Edit" menu?
+
+ A: Both of those operations cause Wireshark to try to build a list of the
+ interfaces that it can open; it does so by getting a list of interfaces and
+ trying to open them. There is probably an OS, driver, or, for Windows,
+ WinPcap bug that causes the system to crash when this happens; see the
+ previous question.
+
+7. Capturing packets
+
+ Q 7.1: When I use Wireshark to capture packets, why do I see only packets to
+ and from my machine, or not see all the traffic I'm expecting to see from or
+ to the machine I'm trying to monitor?
+
+ A: This might be because the interface on which you're capturing is plugged
+ into an Ethernet or Token Ring switch; on a switched network, unicast
+ traffic between two ports will not necessarily appear on other ports - only
+ broadcast and multicast traffic will be sent to all ports.
+
+ Note that even if your machine is plugged into a hub, the "hub" may be a
+ switched hub, in which case you're still on a switched network.
+
+ Note also that on the Linksys Web site, they say that their auto-sensing
+ hubs "broadcast the 10Mb packets to the port that operate at 10Mb only and
+ broadcast the 100Mb packets to the ports that operate at 100Mb only", which
+ would indicate that if you sniff on a 10Mb port, you will not see traffic
+ coming sent to a 100Mb port, and vice versa. This problem has also been
+ reported for Netgear dual-speed hubs, and may exist for other "auto-sensing"
+ or "dual-speed" hubs.
+
+ Some switches have the ability to replicate all traffic on all ports to a
+ single port so that you can plug your analyzer into that single port to
+ sniff all traffic. You would have to check the documentation for the switch
+ to see if this is possible and, if so, to see how to do this. See the switch
+ reference page on the Wireshark Wiki for information on some switches. (Note
+ that it's a Wiki, so you can update or fix that information, or add
+ additional information on those switches or information on new switches,
+ yourself.)
+
+ Note also that many firewall/NAT boxes have a switch built into them; this
+ includes many of the "cable/DSL router" boxes. If you have a box of that
+ sort, that has a switch with some number of Ethernet ports into which you
+ plug machines on your network, and another Ethernet port used to connect to
+ a cable or DSL modem, you can, at least, sniff traffic between the machines
+ on your network and the Internet by plugging the Ethernet port on the router
+ going to the modem, the Ethernet port on the modem, and the machine on which
+ you're running Wireshark into a hub (make sure it's not a switching hub, and
+ that, if it's a dual-speed hub, all three of those ports are running at the
same speed.
- If your machine is not plugged into a switched network or a dual-speed
- hub, or it is plugged into a switched network but the port is set up
- to have all traffic replicated to it, the problem might be that the
- network interface on which you're capturing doesn't support
- "promiscuous" mode, or because your OS can't put the interface into
- promiscuous mode. Normally, network interfaces supply to the host
- only:
+ If your machine is not plugged into a switched network or a dual-speed hub,
+ or it is plugged into a switched network but the port is set up to have all
+ traffic replicated to it, the problem might be that the network interface on
+ which you're capturing doesn't support "promiscuous" mode, or because your
+ OS can't put the interface into promiscuous mode. Normally, network
+ interfaces supply to the host only:
* packets sent to one of that host's link-layer addresses;
* broadcast packets;
* multicast packets sent to a multicast address that the host has
configured the interface to accept.
- Most network interfaces can also be put in "promiscuous" mode, in
- which they supply to the host all network packets they see. Ethereal
- will try to put the interface on which it's capturing into promiscuous
- mode unless the "Capture packets in promiscuous mode" option is turned
- off in the "Capture Options" dialog box, and Tethereal will try to put
+ Most network interfaces can also be put in "promiscuous" mode, in which they
+ supply to the host all network packets they see. Wireshark will try to put
the interface on which it's capturing into promiscuous mode unless the
- -p option was specified. However, some network interfaces don't
- support promiscuous mode, and some OSes might not allow interfaces to
- be put into promiscuous mode.
+ "Capture packets in promiscuous mode" option is turned off in the "Capture
+ Options" dialog box, and TShark will try to put the interface on which it's
+ capturing into promiscuous mode unless the -p option was specified. However,
+ some network interfaces don't support promiscuous mode, and some OSes might
+ not allow interfaces to be put into promiscuous mode.
If the interface is not running in promiscuous mode, it won't see any
traffic that isn't intended to be seen by your machine. It will see
- broadcast packets, and multicast packets sent to a multicast MAC
- address the interface is set up to receive.
+ broadcast packets, and multicast packets sent to a multicast MAC address the
+ interface is set up to receive.
- You should ask the vendor of your network interface whether it
- supports promiscuous mode. If it does, you should ask whoever supplied
- the driver for the interface (the vendor, or the supplier of the OS
- you're running on your machine) whether it supports promiscuous mode
- with that network interface.
+ You should ask the vendor of your network interface whether it supports
+ promiscuous mode. If it does, you should ask whoever supplied the driver for
+ the interface (the vendor, or the supplier of the OS you're running on your
+ machine) whether it supports promiscuous mode with that network interface.
In the case of token ring interfaces, the drivers for some of them, on
- Windows, may require you to enable promiscuous mode in order to
- capture in promiscuous mode. Ask the vendor of the card how to do
- this, or see, for example, this information on promiscuous mode on
- some Madge token ring adapters (note that those cards can have
- promiscuous mode disabled permanently, in which case you can't enable
- it).
+ Windows, may require you to enable promiscuous mode in order to capture in
+ promiscuous mode. See the Wireshark Wiki item on Token Ring capturing for
+ details.
In the case of wireless LAN interfaces, it appears that, when those
- interfaces are promiscuously sniffing, they're running in a
- significantly different mode from the mode that they run in when
- they're just acting as network interfaces (to the extent that it would
- be a significant effor for those drivers to support for promiscuously
- sniffing and acting as regular network interfaces at the same time),
- so it may be that Windows drivers for those interfaces don't support
- promiscuous mode.
-
- Q 5.2: I can't see any TCP packets other than packets to and from my
- machine, even though another sniffer on the network sees those
- packets.
-
- A: You're probably not seeing any packets other than unicast packets
- to or from your machine, and broadcast and multicast packets; a switch
- will normally send to a port only unicast traffic sent to the MAC
- address for the interface on that port, and broadcast and multicast
- traffic - it won't send to that port unicast traffic sent to a MAC
- address for some other interface - and a network interface not in
- promiscuous mode will receive only unicast traffic sent to the MAC
- address for that interface, broadcast traffic, and multicast traffic
- sent to a multicast MAC address the interface is set up to receive.
-
- TCP doesn't use broadcast or multicast, so you will only see your own
- TCP traffic, but UDP services may use broadcast or multicast so you'll
- see some UDP traffic - however, this is not a problem with TCP
- traffic, it's a problem with unicast traffic, as you also won't see
- all UDP traffic between other machines.
+ interfaces are promiscuously sniffing, they're running in a significantly
+ different mode from the mode that they run in when they're just acting as
+ network interfaces (to the extent that it would be a significant effor for
+ those drivers to support for promiscuously sniffing and acting as regular
+ network interfaces at the same time), so it may be that Windows drivers for
+ those interfaces don't support promiscuous mode.
+
+ Q 7.2: When I capture with Wireshark, why can't I see any TCP packets other
+ than packets to and from my machine, even though another analyzer on the
+ network sees those packets?
+
+ A: You're probably not seeing any packets other than unicast packets to or
+ from your machine, and broadcast and multicast packets; a switch will
+ normally send to a port only unicast traffic sent to the MAC address for the
+ interface on that port, and broadcast and multicast traffic - it won't send
+ to that port unicast traffic sent to a MAC address for some other interface
+ - and a network interface not in promiscuous mode will receive only unicast
+ traffic sent to the MAC address for that interface, broadcast traffic, and
+ multicast traffic sent to a multicast MAC address the interface is set up to
+ receive.
+
+ TCP doesn't use broadcast or multicast, so you will only see your own TCP
+ traffic, but UDP services may use broadcast or multicast so you'll see some
+ UDP traffic - however, this is not a problem with TCP traffic, it's a
+ problem with unicast traffic, as you also won't see all UDP traffic between
+ other machines.
I.e., this is probably the same question as this earlier one; see the
response to that question.
- Q 5.3: I'm only seeing ARP packets when I try to capture traffic.
+ Q 7.3: Why am I only seeing ARP packets when I try to capture traffic?
- A: You're probably on a switched network, and running Ethereal on a
- machine that's not sending traffic to the switch and not being sent
- any traffic from other machines on the switch. ARP packets are often
- broadcast packets, which are sent to all switch ports.
+ A: You're probably on a switched network, and running Wireshark on a machine
+ that's not sending traffic to the switch and not being sent any traffic from
+ other machines on the switch. ARP packets are often broadcast packets, which
+ are sent to all switch ports.
I.e., this is probably the same question as this earlier one; see the
response to that question.
- Q 5.4: How do I put an interface into promiscuous mode?
+ Q 7.4: Why am I not seeing any traffic when I try to capture traffic?
+
+ A: Is the machine running Wireshark sending out any traffic on the network
+ interface on which you're capturing, or receiving any traffic on that
+ network, or is there any broadcast traffic on the network or multicast
+ traffic to a multicast group to which the machine running Wireshark belongs?
+
+ If not, this may just be a problem with promiscuous sniffing, either due to
+ running on a switched network or a dual-speed hub, or due to problems with
+ the interface not supporting promiscuous mode; see the response to this
+ earlier question.
+
+ Otherwise, on Windows, see the response to this question and, on a
+ UNIX-flavored OS, see the response to this question.
+
+ Q 7.5: Can Wireshark capture on (my T1/E1 line, SS7 links, etc.)?
+
+ A: Wireshark can only capture on devices supported by libpcap/WinPcap. On
+ most OSes, only devices that can act as network interfaces of the type that
+ support IP are supported as capture devices for libpcap/WinPcap, although
+ the device doesn't necessarily have to be running as an IP interface in
+ order to support traffic capture.
+
+ On Linux and FreeBSD, libpcap 0.8 and later support the API for Endace
+ Measurement Systems' DAG cards, so that a system with one of those cards,
+ and its driver and libraries, installed can capture traffic with those cards
+ with libpcap-based applications. You would either have to have a version of
+ Wireshark built with that version of libpcap, or a dynamically-linked
+ version of Wireshark and a shared libpcap library with DAG support, in order
+ to do so with Wireshark. You should ask Endace whether that could be used to
+ capture traffic on, for example, your T1/E1 link. See the SS7 capture setup
+ page on the Wireshark Wiki for current information on capturing SS7 traffic
+ on TDM links.
- A: By not disabling promiscuous mode when running Ethereal or
- Tethereal.
+ Q 7.6: How do I put an interface into promiscuous mode?
+
+ A: By not disabling promiscuous mode when running Wireshark or TShark.
Note, however, that:
- * the form of promiscuous mode that libpcap (the library that
- programs such as tcpdump, Ethereal, etc. use to do packet capture)
- turns on will not necessarily be shown if you run ifconfig on the
- interface on a UNIX system;
- * some network interfaces might not support promiscuous mode, and
- some drivers might not allow promiscuous mode to be turned on -
- see this earlier question for more information on that;
+ * the form of promiscuous mode that libpcap (the library that programs
+ such as tcpdump, Wireshark, etc. use to do packet capture) turns on will
+ not necessarily be shown if you run ifconfig on the interface on a UNIX
+ system;
+ * some network interfaces might not support promiscuous mode, and some
+ drivers might not allow promiscuous mode to be turned on - see this
+ earlier question for more information on that;
* the fact that you're not seeing any traffic, or are only seeing
- broadcast traffic, or aren't seeing any non-broadcast traffic
- other than traffic to or from the machine running Ethereal, does
- not mean that promiscuous mode isn't on - see this earlier
- question for more information on that.
+ broadcast traffic, or aren't seeing any non-broadcast traffic other than
+ traffic to or from the machine running Wireshark, does not mean that
+ promiscuous mode isn't on - see this earlier question for more
+ information on that.
I.e., this is probably the same question as this earlier one; see the
response to that question.
- Q 5.5: I can set a display filter just fine, but capture filters don't
- work.
+ Q 7.7: I can set a display filter just fine; why don't capture filters work?
- A: Capture filters currently use a different syntax than display
- filters. Here's the corresponding section from the ethereal(1) man
- page:
+ A: Capture filters currently use a different syntax than display filters.
+ Here's the corresponding section from the wireshark(1) man page:
- "Display filters in Ethereal are very powerful; more fields are
- filterable in Ethereal than in other protocol analyzers, and the
- syntax you can use to create your filters is richer. As Ethereal
- progresses, expect more and more protocol fields to be allowed in
- display filters.
+ "Display filters in Wireshark are very powerful; more fields are filterable
+ in Wireshark than in other protocol analyzers, and the syntax you can use to
+ create your filters is richer. As Wireshark progresses, expect more and more
+ protocol fields to be allowed in display filters.
- Packet capturing is performed with the pcap library. The capture
- filter syntax follows the rules of the pcap library. This syntax is
- different from the display filter syntax."
+ Packet capturing is performed with the pcap library. The capture filter
+ syntax follows the rules of the pcap library. This syntax is different from
+ the display filter syntax."
- The capture filter syntax used by libpcap can be found in the
- tcpdump(8) man page.
+ The capture filter syntax used by libpcap can be found in the tcpdump(8) man
+ page.
- Q 5.6: I'm entering valid capture filters, but I still get "parse
- error" errors.
+ Q 7.8: I'm entering valid capture filters; why do I still get "parse error"
+ errors?
A: There is a bug in some versions of libpcap/WinPcap that cause it to
report parse errors even for valid expressions if a previous filter
expression was invalid and got a parse error.
- Try exiting and restarting Ethereal; if you are using a version of
- libpcap/WinPcap with this bug, this will "erase" its memory of the
- previous parse error. If the capture filter that got the "parse error"
- now works, the earlier error with that filter was probably due to this
- bug.
-
- The bug was fixed in libpcap 0.6; 0.4[.x] and 0.5[.x] versions of
- libpcap have this bug, but 0.6[.x] and later versions don't.
-
- Versions of WinPcap prior to 2.3 are based on pre-0.6 versions of
- libpcap, and have this bug; WinPcap 2.3 is based on libpcap 0.6.2, and
- doesn't have this bug.
-
- If you are running Ethereal on a UNIX-flavored platform, run "ethereal
- -v", or select "About Ethereal..." from the "Help" menu in Ethereal,
- to see what version of libpcap it's using. If it's not 0.6 or later,
- you will need either to upgrade your OS to get a later version of
- libpcap, or will need to build and install a later version of libpcap
- from the tcpdump.org Web site and then recompile Ethereal from source
- with that later version of libpcap.
-
- If you are running Ethereal on Windows with a pre-2.3 version of
- WinPcap, you will need to un-install WinPcap and then download and
- install WinPcap 2.3.
-
- Q 5.7: I saved a filter and tried to use its name to filter the
- display, but I got an "Unexpected end of filter string" error.
-
- A: You cannot use the name of a saved display filter as a filter. To
- filter the display, you can enter a display filter expression - not
- the name of a saved display filter - in the "Filter:" box at the
- bottom of the display, and type the key or press the "Apply" button
- (that does not require you to have a saved filter), or, if you want to
- use a saved filter, you can press the "Filter:" button, select the
- filter in the dialog box that pops up, and press the "OK" button.
-
- Q 5.8: Why am I seeing lots of packets with incorrect TCP checksums?
-
- A: If the packets that have incorrect TCP checksums are all being sent
- by the machine on which Ethereal is running, this is probably because
- the network interface on which you're capturing does TCP checksum
- offloading. That means that the TCP checksum is added to the packet by
- the network interface, not by the OS's TCP/IP stack; when capturing on
- an interface, packets being sent by the host on which you're capturing
- are directly handed to the capture interface by the OS, which means
- that they are handed to the capture interface without a TCP checksum
- being added to them.
-
- The only way to prevent this from happening would be to disable TCP
- checksum offloading, but
- 1. that might not even be possible on some OSes;
- 2. that could reduce networking performance significantly.
-
- However, you can disable the check that Ethereal does of the TCP
- checksum, so that it won't report any packets as having TCP checksum
- errors, and so that it won't refuse to do TCP reassembly due to a
- packet having an incorrect TCP checksum. That can be set as an
- Ethereal preference by selecting "Preferences" from the "Edit" menu,
- opening up the "Protocols" list in the left-hand pane of the
- "Preferences" dialog box, selecting "TCP", from that list, turning off
- the "Check the validity of the TCP checksum when possible" option,
- clicking "Save" if you want to save that setting in your preference
- file, and clicking "OK".
-
- It can also be set on the Ethereal or Tethereal command line with a -o
- tcp.check_checksum:false command-line flag, or manually set in your
- preferences file by adding a tcp.check_checksum:false line.
-
- Q 5.9: I've just installed Ethereal, and the traffic on my local LAN
- is boring.
+ Try exiting and restarting Wireshark; if you are using a version of
+ libpcap/WinPcap with this bug, this will "erase" its memory of the previous
+ parse error. If the capture filter that got the "parse error" now works, the
+ earlier error with that filter was probably due to this bug.
+
+ The bug was fixed in libpcap 0.6; 0.4[.x] and 0.5[.x] versions of libpcap
+ have this bug, but 0.6[.x] and later versions don't.
+
+ Versions of WinPcap prior to 2.3 are based on pre-0.6 versions of libpcap,
+ and have this bug; WinPcap 2.3 is based on libpcap 0.6.2, and doesn't have
+ this bug.
+
+ If you are running Wireshark on a UNIX-flavored platform, run "wireshark
+ -v", or select "About Wireshark..." from the "Help" menu in Wireshark, to
+ see what version of libpcap it's using. If it's not 0.6 or later, you will
+ need either to upgrade your OS to get a later version of libpcap, or will
+ need to build and install a later version of libpcap from the tcpdump.org
+ Web site and then recompile Wireshark from source with that later version of
+ libpcap.
+
+ If you are running Wireshark on Windows with a pre-2.3 version of WinPcap,
+ you will need to un-install WinPcap and then download and install WinPcap
+ 2.3.
+
+ Q 7.9: How can I capture packets with CRC errors?
+
+ A: Wireshark can capture only the packets that the packet capture library -
+ libpcap on UNIX-flavored OSes, and the WinPcap port to Windows of libpcap on
+ Windows - can capture, and libpcap/WinPcap can capture only the packets that
+ the OS's raw packet capture mechanism (or the WinPcap driver, and the
+ underlying OS networking code and network interface drivers, on Windows)
+ will allow it to capture.
+
+ Unless the OS always supplies packets with errors such as invalid CRCs to
+ the raw packet capture mechanism, or can be configured to do so, invalid
+ CRCs to the raw packet capture mechanism, Wireshark - and other programs
+ that capture raw packets, such as tcpdump - cannot capture those packets.
+ You will have to determine whether your OS needs to be so configured and, if
+ so, can be so configured, configure it if necessary and possible, and make
+ whatever changes to libpcap and the packet capture program you're using are
+ necessary, if any, to support capturing those packets.
+
+ Most OSes probably do not support capturing packets with invalid CRCs on
+ Ethernet, and probably do not support it on most other link-layer types.
+ Some drivers on some OSes do support it, such as some Ethernet drivers on
+ FreeBSD; in those OSes, you might always get those packets, or you might
+ only get them if you capture in promiscuous mode (you'd have to determine
+ which is the case).
+
+ Note that libpcap does not currently supply to programs that use it an
+ indication of whether the packet's CRC was invalid (because the drivers
+ themselves do not supply that information to the raw packet capture
+ mechanism); therefore, Wireshark will not indicate which packets had CRC
+ errors unless the FCS was captured (see the next question) and you're using
+ Wireshark 0.9.15 and later, in which case Wireshark will check the CRC and
+ indicate whether it's correct or not.
+
+ Q 7.10: How can I capture entire frames, including the FCS?
+
+ A: Wireshark can only capture data that the packet capture library - libpcap
+ on UNIX-flavored OSes, and the WinPcap port to Windows of libpcap on Windows
+ - can capture, and libpcap/WinPcap can capture only the data that the OS's
+ raw packet capture mechanism (or the WinPcap driver, and the underlying OS
+ networking code and network interface drivers, on Windows) will allow it to
+ capture.
+
+ For any particular link-layer network type, unless the OS supplies the FCS
+ of a frame as part of the frame, or can be configured to do so, Wireshark -
+ and other programs that capture raw packets, such as tcpdump - cannot
+ capture the FCS of a frame. You will have to determine whether your OS needs
+ to be so configured and, if so, can be so configured, configure it if
+ necessary and possible, and make whatever changes to libpcap and the packet
+ capture program you're using are necessary, if any, to support capturing the
+ FCS of a frame.
+
+ Most OSes do not support capturing the FCS of a frame on Ethernet, and
+ probably do not support it on most other link-layer types. Some drivres on
+ some OSes do support it, such as some (all?) Ethernet drivers on NetBSD and
+ possibly the driver for Apple's gigabit Ethernet interface in Mac OS X; in
+ those OSes, you might always get the FCS, or you might only get the FCS if
+ you capture in promiscuous mode (you'd have to determine which is the case).
+
+ Versions of Wireshark prior to 0.9.15 will not treat an Ethernet FCS in a
+ captured packet as an FCS. 0.9.15 and later will attempt to determine
+ whether there's an FCS at the end of the frame and, if it thinks there is,
+ will display it as such, and will check whether it's the correct CRC-32
+ value or not.
+
+ Q 7.11: I'm capturing packets on a machine on a VLAN; why don't the packets
+ I'm capturing have VLAN tags?
+
+ A: You might be capturing on what might be called a "VLAN interface" - the
+ way a particular OS makes VLANs plug into the networking stack might, for
+ example, be to have a network device object for the physical interface,
+ which takes VLAN packets, strips off the VLAN header and constructs an
+ Ethernet header, and passes that packet to an internal network device object
+ for the VLAN, which then passes the packets onto various higher-level
+ protocol implementations.
+
+ In order to see the raw Ethernet packets, rather than "de-VLANized" packets,
+ you would have to capture not on the virtual interface for the VLAN, but on
+ the interface corresponding to the physical network device, if possible. See
+ the Wireshark Wiki item on VLAN capturing for details.
+
+ Q 7.12: Why does Wireshark hang after I stop a capture?
+
+ A: The most likely reason for this is that Wireshark is trying to look up an
+ IP address in the capture to convert it to a name (so that, for example, it
+ can display the name in the source address or destination address columns),
+ and that lookup process is taking a very long time.
+
+ Wireshark calls a routine in the OS of the machine on which it's running to
+ convert of IP addresses to the corresponding names. That routine probably
+ does one or more of:
+ * a search of a system file listing IP addresses and names;
+ * a lookup using DNS;
+ * on UNIX systems, a lookup using NIS;
+ * on Windows systems, a NetBIOS-over-TCP query.
- A: We have a collection of strange and exotic sample capture files at
- http://www.ethereal.com/sample/
-
- Q 5.10: When I run Ethereal on Solaris 8, it dies with a Bus Error
- when I start it.
-
- A: Some versions of the GTK+ library from www.sunfreeware.org appear
- to be buggy, causing Ethereal to drop core with a Bus Error.
- Un-install those packages, and try getting the 1.2.10 version from
- that site, or the version from The Written Word, or the version from
- Sun's GNOME distribution, or the version from the supplemental
- software CD that comes with the Solaris media kit, or build it from
- source from the GTK Web site. Update the GLib library to the 1.2.10
- version, from the same source, as well. (If you get the 1.2.10
- versions from www.sunfreeware.org, and the problem persists,
- un-install them and try installing one of the other versions
- mentioned.)
-
- Similar problems may exist with older versions of GTK+ for earlier
- versions of Solaris.
-
- Q 5.11: I'm running Ethereal on Linux; why do my time stamps have only
- 100ms resolution, rather than 1us resolution?
+ If a DNS server that's used in an address lookup is not responding, the
+ lookup will fail, but will only fail after a timeout while the system
+ routine waits for a reply.
+
+ In addition, on Windows systems, if the DNS lookup of the address fails,
+ either because the server isn't responding or because there are no records
+ in the DNS that could be used to map the address to a name, a
+ NetBIOS-over-TCP query will be made. That query involves sending a message
+ to the NetBIOS-over-TCP name service on that machine, asking for the name
+ and other information about the machine. If the machine isn't running
+ software that responds to those queries - for example, many non-Windows
+ machines wouldn't be running that software - the lookup will only fail after
+ a timeout. Those timeouts can cause the lookup to take a long time.
+
+ If you disable network address-to-name translation - for example, by turning
+ off the "Enable network name resolution" option in the "Capture Options"
+ dialog box for starting a network capture - the lookups of the address won't
+ be done, which may speed up the process of reading the capture file after
+ the capture is stopped. You can make that setting the default by selecting
+ "Preferences" from the "Edit" menu, turning off the "Enable network name
+ resolution" option in the "Name resolution" options in the preferences
+ disalog box, and using the "Save" button in that dialog box; note that this
+ will save all your current preference settings.
+
+ If Wireshark hangs when reading a capture even with network name resolution
+ turned off, there might, for example, be a bug in one of Wireshark's
+ dissectors for a protocol causing it to loop infinitely. If you're not
+ running the most recent release of Wireshark, you should first upgrade to
+ that release, as, if there's a bug of that sort, it might've been fixed in a
+ release after the one you're running. If the hang occurs in the most recent
+ release of Wireshark, the bug should be reported to the Wireshark
+ developers' mailing list at wireshark-dev@wireshark.org.
+
+ On UNIX-flavored OSes, please try to force Wireshark to dump core, by
+ sending it a SIGABRT signal (usually signal 6) with the kill command, and
+ then get a stack trace if you have a debugger installed. A stack trace can
+ be obtained by using your debugger (gdb in this example), the Wireshark
+ binary, and the resulting core file. Here's an example of how to use the gdb
+ command backtrace to do so.
+ $ gdb wireshark core
+ (gdb) backtrace
+ ..... prints the stack trace
+ (gdb) quit
+ $
- A: Ethereal gets time stamps from libpcap/WinPcap, and libpcap/WinPcap
- get them from the OS kernel, so Ethereal - and any other program using
- libpcap, such as tcpdump - is at the mercy of the time stamping code
- in the OS for time stamps.
-
- At least on x86-based machines, Linux can get high-resolution time
- stamps on newer processors with the Time Stamp Counter (TSC) register;
- for example, Intel x86 processors, starting with the Pentium Pro, and
- including all x86 processors since then, have had a TSC, and other
- vendors probably added the TSC at some point to their families of x86
- processors.
-
- The Linux kernel must be configured with the CONFIG_X86_TSC option
- enabled in order to use the TSC. Make sure this option is enabled in
- your kernel.
-
- In addition, some Linux distributions may have bugs in their versions
- of the kernel that cause packets not to be given high-resolution time
- stamps even if the TSC is enabled. See, for example, bug 61111 for Red
- Hat Linux 7.2. If your distribution has a bug such as this, you may
- have to run a standard kernel from kernel.org in order to get
- high-resolution time stamps.
-
- Q 5.12: I'm capturing packets on {Windows 95, Windows 98, Windows Me};
- why are the time stamps on packets wrong?
-
- A: This is due to a bug in WinPcap. The bug should be fixed in the
- WinPcap 3.0 beta release - note that it's an beta release, so it may
- be buggier than the current production release of WinPcap; please
- report those bugs to the WinPcap developers, and help them try to
- track down the problem, so that they can fix it for the final release.
-
- Q 5.13: When I try to run Ethereal on Windows, it fails to run because
- it can't find packet.dll.
-
- A: In older versions of Ethereal, there were two binary distributions
- available for Windows, one that supported capturing packets, and one
- that didn't. The version that supported capturing packets required
- that you install the WinPcap driver; if you didn't install it, it
- would fail to run because it couldn't find packet.dll.
-
- The current version of Ethereal has only one binary distribution for
- Windows; that version will check whether WinPcap is installed and, if
- it's not, will disable support for packet capture.
-
- The WinPcap driver and libraries can be downloaded from the WinPcap
- Web site, the local mirror of the WinPcap Web site, or the
- Wiretapped.net mirror of the WinPcap site.
-
- Q 5.14: Why does some network interface on my machine not show up in
- the list of interfaces in the "Interface:" field in the dialog box
- popped up by "Capture->Start", and/or why does Ethereal give me an
- error if I try to capture on that interface?
-
- A: If you are running Ethereal on a UNIX-flavored platform, you may
- need to run Ethereal from an account with sufficient privileges to
- capture packets, such as the super-user account. Only those interfaces
- that Ethereal can open for capturing show up in that list; if you
- don't have sufficient privileges to capture on any interfaces, no
- interfaces will show up in the list.
-
- If you are running Ethereal on Windows NT 4.0, Windows 2000, Windows
- XP, or Windows Server, and this is the first time you have run a
- WinPcap-based program (such as Ethereal, or Tethereal, or WinDump, or
+ The core dump file may be named "wireshark.core" rather than "core" on some
+ platforms (e.g., BSD systems).
+
+ Also, if at all possible, please send a copy of the capture file that caused
+ the problem; when capturing packets, Wireshark normally writes captured
+ packets to a temporary file, which will probably be in /tmp or /var/tmp on
+ UNIX-flavored OSes, \TEMP on the main system disk (normally C:) on Windows
+ 9x/Me/NT 4.0, and \Documents and Settings\your login name\Local
+ Settings\Temp on the main system disk on Windows 2000/Windows XP/Windows
+ Server 2003, so the capture file will probably be there. It will have a name
+ beginning with ether, with some mixture of letters and numbers after that.
+ Please don't send a trace file greater than 1 MB when compressed; instead,
+ make it available via FTP or HTTP, or say it's available but leave it up to
+ a developer to ask for it. If the trace file contains sensitive information
+ (e.g., passwords), then please do not send it.
+
+8. Capturing packets on Windows
+
+ Q 8.1: I'm running Wireshark on Windows; why does some network interface on
+ my machine not show up in the list of interfaces in the "Interface:" field
+ in the dialog box popped up by "Capture->Start", and/or why does Wireshark
+ give me an error if I try to capture on that interface?
+
+ A: If you are running Wireshark on Windows NT 4.0, Windows 2000, Windows XP,
+ or Windows Server 2003, and this is the first time you have run a
+ WinPcap-based program (such as Wireshark, or TShark, or WinDump, or
Analyzer, or...) since the machine was rebooted, you need to run that
- program from an account with administrator privileges; once you have
- run such a program, you will not need administrator privileges to run
- any such programs until you reboot.
-
- If you are running on a UNIX-flavored platform and have sufficient
- privileges, or if you are running on Windows 95/98/Me, or if you are
- running on Windows NT 4.0/2000/XP/Server and have administrator
- privileges or a WinPcap program has been run with those privileges
- since the machine rebooted, then note that Ethereal relies on the
- libpcap library, and on the facilities that come with the OS on which
- it's running in order to do captures; on Windows, it also relies on
- the device driver that comes with WinPcap (which is a version of
- libpcap for Windows).
-
- Therefore, if the OS, the libpcap library, or the WinPcap driver don't
- support capturing on a particular network interface device, Ethereal
- won't be able to capture on that device.
-
- On Linux, note that you need to have "packet socket" support enabled
- in your kernel; see the "Packet socket" item in the Linux
- "Configure.help" file.
-
- On BSD, note that you need to have BPF support enabled in your kernel;
- see the documentation for your system for information on how to enable
- BPF support (if it's not enabled by default on your system).
-
- On DEC OSF/1, Digital UNIX, or Tru64 UNIX, note that you need to have
- packet filtering support in your kernel; the doconfig command will
- allow you to configure and build a new kernel with that option.
-
- On Windows, note that:
- * 2.02 and earlier versions of the WinPcap driver and library that
- Ethereal uses for packet capture didn't support Token Ring
- interfaces; the current version, 2.3, does support Token Ring, and
- the current version of Ethereal works with (and, in fact,
- requires) WinPcap 2.1 or later.
- If you are having problems capturing on Token Ring interfaces, and
- you have WinPcap 2.02 or an earlier version of WinPcap installed,
- you should uninstall WinPcap, download and install the current
- version of WinPcap, and then install the latest version of
- Ethereal.
- * On Windows 95, 98, or Me, sometimes more than one interface will
- be given the same name; if that is the case, you will only be able
- to capture on one of those interfaces - it's not clear to which
- one the name, when used in a WinPcap application, will refer. For
- example, if you have a PPP serial interface and a VPN interface,
- they might show up with the same name, for example "ppp-mac", and
- if you try to capture on "ppp-mac", it might not capture on the
- interface you're currently using. In that case, you might, for
- example, have to remove the VPN interface from the system in order
- to capture on the PPP serial interface.
- * WinPcap doesn't support PPP WAN interfaces on Windows
- NT/2000/XP/Server, so Ethereal cannot capture packets on those
- devices when running on Windows NT/2000/XP/Server. Regular dial-up
- lines, ISDN lines, and various other lines such as T1/E1 lines are
- all PPP interfaces. This may cause the interface not to show up on
- the list of interfaces in the "Capture Options" dialog.
- * WinPcap currently does not support multiprocessor machines (note
- that machines with a single multi-threaded processor, such as
- Intel's new multi-threaded x86 processors, are multiprocessor
- machines as far as the OS and WinPcap are concerned), and recent
- versions refuse to operate if they detect that they're running on
- a multiprocessor machine, which means that they may not show any
- network interfaces.
-
- If you are having trouble capturing on a particular network interface,
- and you've made sure that (on platforms that require it) you've
- arranged that packet capture support is present, as per the above,
- first try capturing on that device with tcpdump - or, on Windows, the
- tcpdump port to Windows, named WinDump; see the WinDump Web site, the
- local mirror of the WinDump Web site, or the Wiretapped.net mirror of
- the WinDump site, for information on using WinDump.
-
- If you can capture on the interface with tcpdump/WinDump, send mail to
- ethereal-users@ethereal.com giving full details of the problem,
- including
- * the operating system you're using, and the version of that
- operating system (for Linux, give both the version number of the
- kernel and the name and version number of the distribution you're
- using);
+ program from an account with administrator privileges; once you have run
+ such a program, you will not need administrator privileges to run any such
+ programs until you reboot.
+
+ If you are running on Windows 95/98/Me, or if you are running on Windows NT
+ 4.0/Windows 2000/Windows XP/Windows Server 2003 and have administrator
+ privileges or a WinPcap-based program has been run with those privileges
+ since the machine rebooted, this problem might clear up if you completely
+ un-install WinPcap and then re-install it.
+
+ If that doesn't work, then note that Wireshark relies on the WinPcap
+ library, on the WinPcap device driver, and on the facilities that come with
+ the OS on which it's running in order to do captures.
+
+ Therefore, if the OS, the WinPcap library, or the WinPcap driver don't
+ support capturing on a particular network interface device, Wireshark won't
+ be able to capture on that device.
+
+ Note that:
+ 1. 2.02 and earlier versions of the WinPcap driver and library that
+ Wireshark uses for packet capture didn't support Token Ring interfaces;
+ versions 2.1 and later support Token Ring, and the current version of
+ Wireshark works with (and, in fact, requires) WinPcap 2.1 or later.
+ If you are having problems capturing on Token Ring interfaces, and you
+ have WinPcap 2.02 or an earlier version of WinPcap installed, you should
+ uninstall WinPcap, download and install the current version of WinPcap,
+ and then install the latest version of Wireshark.
+ 2. On Windows 95, 98, or Me, sometimes more than one interface will be
+ given the same name; if that is the case, you will only be able to
+ capture on one of those interfaces - it's not clear to which one the
+ name, when used in a WinPcap-based application, will refer. For example,
+ if you have a PPP serial interface and a VPN interface, they might show
+ up with the same name, for example "ppp-mac", and if you try to capture
+ on "ppp-mac", it might not capture on the interface you're currently
+ using. In that case, you might, for example, have to remove the VPN
+ interface from the system in order to capture on the PPP serial
+ interface.
+ 3. WinPcap 2.3 has problems supporting PPP WAN interfaces on Windows NT
+ 4.0, Windows 2000, Windows XP, and Windows Server 2003, and, to avoid
+ those problems, support for PPP WAN interfaces on those versions of
+ Windows has been disabled in WinPcap 3.0. Regular dial-up lines, ISDN
+ lines, ADSL connections using PPPoE or PPPoA, and various other lines
+ such as T1/E1 lines are all PPP interfaces, so those interfaces might
+ not show up on the list of interfaces in the "Capture Options" dialog on
+ those OSes.
+ On Windows 2000, Windows XP, and Windows Server 2003, but not Windows NT
+ 4.0 or Windows Vista Beta 1, you should be able to capture on the
+ "GenericDialupAdapter" with WinPcap 3.1. (3.1 beta releases called it
+ the "NdisWanAdapter"; if you're using a 3.1 beta release, you should
+ un-install it and install the final 3.1 release.) See the Wireshark Wiki
+ item on PPP capturing for details.
+ 4. WinPcap prior to 3.0 does not support multiprocessor machines (note that
+ machines with a single multi-threaded processor, such as Intel's new
+ multi-threaded x86 processors, are multiprocessor machines as far as the
+ OS and WinPcap are concerned), and recent 2.x versions of WinPcap refuse
+ to operate if they detect that they're running on a multiprocessor
+ machine, which means that they may not show any network interfaces. You
+ will need to use WinPcap 3.0 to capture on a multiprocessor machine.
+
+ If an interface doesn't show up in the list of interfaces in the
+ "Interface:" field, and you know the name of the interface, try entering
+ that name in the "Interface:" field and capturing on that device.
+
+ If the attempt to capture on it succeeds, the interface is somehow not being
+ reported by the mechanism Wireshark uses to get a list of interfaces. Try
+ listing the interfaces with WinDump; see the WinDump Web site for
+ information on using WinDump.
+
+ You would run WinDump with the -D flag; if it lists the interface, please
+ report this to wireshark-dev@wireshark.org giving full details of the
+ problem, including
+ * the operating system you're using, and the version of that operating
+ system;
* the type of network device you're using;
- * the error message you get from Ethereal.
+ * the output of WinDump.
- If you cannot capture on the interface with tcpdump/WinDump, this is
- almost certainly a problem with one or more of:
+ If WinDump does not list the interface, this is almost certainly a problem
+ with one or more of:
* the operating system you're using;
* the device driver for the interface you're using;
- * the libpcap/WinPcap library and, if this is Windows, the WinPcap
- device driver;
+ * the WinPcap library and/or the WinPcap device driver;
- so:
- * if you are using Windows, first check the WinPcap FAQ, the local
- mirror of that FAQ, or the Wiretapped.net mirror of that FAQ, to
- see if your problem is mentioned there. If not, then see the
- WinPcap support page (or the local mirror of that page) - check
- the "Submitting bugs" section;
- * if you are using some Linux distribution, some version of BSD, or
- some other UNIX-flavored OS, you should report the problem to the
- company or organization that produces the OS (in the case of a
- Linux distribution, report the problem to whoever produces the
- distribution).
-
- You may also want to ask the ethereal-users@ethereal.com and, if this
- is a UNIX-flavored platform, tcpdump-workers@tcpdump.org mailing lists
- to see if anybody happens to know about the problem and know a
- workaround or fix for the problem. In your mail, please give full
- details of the problem, as described above, and also indicate that the
- problem occurs with tcpdump/WinDump, not just with Ethereal.
-
- Q 5.15: I'm running Ethereal on Windows NT/2000/XP/Server; my machine
- has a PPP (dial-up POTS, ISDN, etc.) interface, and it shows up in the
- "Interface" item in the "Capture Options" dialog box. Why can no
- packets be sent on or received from that network while I'm trying to
- capture traffic on that interface?
+ so first check the WinPcap FAQ or the Wiretapped.net mirror of that FAQ, to
+ see if your problem is mentioned there. If not, then see the WinPcap support
+ page - check the "Submitting bugs" section.
- A: WinPcap doesn't support PPP WAN interfaces on Windows
- NT/2000/XP/Server; one symptom that may be seen is that attempts to
- capture in promiscuous mode on the interface cause the interface to be
- incapable of sending or receiving packets. You can disable promiscuous
- mode using the -p command-line flag or the item in the "Capture
- Preferences" dialog box, but this may mean that outgoing packets, or
- incoming packets, won't be seen in the capture.
+ If you are having trouble capturing on a particular network interface, first
+ try capturing on that device with WinDump; see the WinDump Web site for
+ information on using WinDump.
- Q 5.16: I'm running Ethereal on Windows 95/98/Me, on a machine with
- more than one network adapter of the same type; Ethereal shows all of
- those adapters with the same name, but I can't use any of those
- adapters other than the first one.
-
- A: Unfortunately, Windows 95/98/Me gives the same name to multiple
- instances of the type of same network adapter. Therefore, WinPcap
- cannot distinguish between them, so a WinPcap-based application can
- capture only on the first such interface; Ethereal is a
- libpcap/WinPcap-based application.
+ If you can capture on the interface with WinDump, send mail to
+ wireshark-users@wireshark.org giving full details of the problem, including
+ * the operating system you're using, and the version of that operating
+ system;
+ * the type of network device you're using;
+ * the error message you get from Wireshark.
- Q 5.17: I have an XXX network card on my machine; if I try to capture
- on it, my machine crashes or resets itself.
+ If you cannot capture on the interface with WinDump, this is almost
+ certainly a problem with one or more of:
+ * the operating system you're using;
+ * the device driver for the interface you're using;
+ * the WinPcap library and/or the WinPcap device driver;
+
+ so first check the WinPcap FAQ or the Wiretapped.net mirror of that FAQ, to
+ see if your problem is mentioned there. If not, then see the WinPcap support
+ page - check the "Submitting bugs" section.
+
+ You may also want to ask the wireshark-users@wireshark.org and the
+ winpcap-users@winpcap.org mailing lists to see if anybody happens to know
+ about the problem and know a workaround or fix for the problem. (Note that
+ you will have to subscribe to that list in order to be allowed to mail to
+ it; see the WinPcap support page for information on the mailing list.) In
+ your mail, please give full details of the problem, as described above, and
+ also indicate that the problem occurs with WinDump, not just with Wireshark.
+
+ Q 8.2: I'm running Wireshark on Windows; why do no network interfaces show
+ up in the list of interfaces in the "Interface:" field in the dialog box
+ popped up by "Capture->Start"?
+
+ A: This is really the same question as the previous one; see the response to
+ that question.
+
+ Q 8.3: I'm running Wireshark on Windows; why doesn't my serial port/ADSL
+ modem/ISDN modem show up in the list of interfaces in the "Interface:" field
+ in the dialog box popped up by "Capture->Start"?
+
+ A: Internet access on those devices is often done with the Point-to-Point
+ (PPP) protocol; WinPcap 2.3 has problems supporting PPP WAN interfaces on
+ Windows NT 4.0, Windows 2000, Windows XP, and Windows Server 2003, and, to
+ avoid those problems, support for PPP WAN interfaces on those versions of
+ Windows has been disabled in WinPcap 3.0.
+
+ On Windows 2000, Windows XP, and Windows Server 2003, but not Windows NT 4.0
+ or Windows Vista Beta 1, you should be able to capture on the
+ "GenericDialupAdapter" with WinPcap 3.1. (3.1 beta releases called it the
+ "NdisWanAdapter"; if you're using a 3.1 beta release, you should un-install
+ it and install the final 3.1 release.) See the Wireshark Wiki item on PPP
+ capturing for details.
+
+ Q 8.4: I'm running Wireshark on Windows NT 4.0/Windows 2000/Windows
+ XP/Windows Server 2003; my machine has a PPP (dial-up POTS, ISDN, etc.)
+ interface, and it shows up in the "Interface" item in the "Capture Options"
+ dialog box. Why can no packets be sent on or received from that network
+ while I'm trying to capture traffic on that interface?
+
+ A: Some versions of WinPcap have problems with PPP WAN interfaces on Windows
+ NT 4.0, Windows 2000, Windows XP, and Windows Server 2003; one symptom that
+ may be seen is that attempts to capture in promiscuous mode on the interface
+ cause the interface to be incapable of sending or receiving packets. You can
+ disable promiscuous mode using the -p command-line flag or the item in the
+ "Capture Preferences" dialog box, but this may mean that outgoing packets,
+ or incoming packets, won't be seen in the capture.
+
+ On Windows 2000, Windows XP, and Windows Server 2003, but not Windows NT 4.0
+ or Windows Vista Beta 1, you should be able to capture on the
+ "GenericDialupAdapter" with WinPcap 3.1. (3.1 beta releases called it the
+ "NdisWanAdapter"; if you're using a 3.1 beta release, you should un-install
+ it and install the final 3.1 release.) See the Wireshark Wiki item on PPP
+ capturing for details.
+
+ Q 8.5: I'm running Wireshark on Windows 95/98/Me, on a machine with more
+ than one network adapter of the same type; why does Wireshark show all of
+ those adapters with the same name, not letting me use any of those adapters
+ other than the first one?
+
+ A: Unfortunately, Windows 95/98/Me gives the same name to multiple instances
+ of the type of same network adapter. Therefore, WinPcap cannot distinguish
+ between them, so a WinPcap-based application can capture only on the first
+ such interface; Wireshark is a libpcap/WinPcap-based application.
+
+ Q 8.6: I'm running Wireshark on Windows; why am I not seeing any traffic
+ being sent by the machine running Wireshark?
+
+ A: If you are running some form of VPN client software, it might be causing
+ this problem; people have seen this problem when they have Check Point's VPN
+ software installed on their machine. If that's the cause of the problem, you
+ will have to remove the VPN software in order to have Wireshark (or any
+ other application using WinPcap) see outgoing packets; unfortunately,
+ neither we nor the WinPcap developers know any way to make WinPcap and the
+ VPN software work well together.
+
+ Also, some drivers for Windows (especially some wireless network interface
+ drivers) apparently do not, when running in promiscuous mode, arrange that
+ outgoing packets are delivered to the software that requested that the
+ interface run promiscuously; try turning promiscuous mode off.
+
+ Q 8.7: When I capture on Windows in promiscuous mode, I can see packets
+ other than those sent to or from my machine; however, those packets show up
+ with a "Short Frame" indication, unlike packets to or from my machine. What
+ should I do to arrange that I see those packets in their entirety?
+
+ A: In at least some cases, this appears to be the result of PGPnet running
+ on the network interface on which you're capturing; turn it off on that
+ interface.
+
+ Q 8.8: I'm capturing packets on {Windows 95, Windows 98, Windows Me}; why
+ are the time stamps on packets wrong?
+
+ A: This is due to a bug in WinPcap. The bug should be fixed in WinPcap 3.0
+ and later releases.
+
+ Q 8.9: I'm trying to capture 802.11 traffic on Windows; why am I not seeing
+ any packets?
+
+ A: At least some 802.11 card drivers on Windows appear not to see any
+ packets if they're running in promiscuous mode. Try turning promiscuous mode
+ off; you'll only be able to see packets sent by and received by your
+ machine, not third-party traffic, and it'll look like Ethernet traffic and
+ won't include any management or control frames, but that's a limitation of
+ the card drivers.
+
+ See MicroLogix's list of cards supported with WinPcap for information on
+ support of various adapters and drivers with WinPcap.
+
+ Q 8.10: I'm trying to capture 802.11 traffic on Windows; why am I seeing
+ packets received by the machine on which I'm capturing traffic, but not
+ packets sent by that machine?
+
+ A: This appears to be another problem with promiscuous mode; try turning it
+ off.
+
+ Q 8.11: I'm trying to capture Ethernet VLAN traffic on Windows, and I'm
+ capturing on a "raw" Ethernet device rather than a "VLAN interface", so that
+ I can see the VLAN headers; why am I seeing packets received by the machine
+ on which I'm capturing traffic, but not packets sent by that machine?
+
+ A: The way the Windows networking code works probably means that packets are
+ sent on a "VLAN interface" rather than the "raw" device, so packets sent by
+ the machine will only be seen when you capture on the "VLAN interface". If
+ so, you will be unable to see outgoing packets when capturing on the "raw"
+ device, so you are stuck with a choice between seeing VLAN headers and
+ seeing outgoing packets.
+
+9. Capturing packets on UN*Xes
+
+ Q 9.1: I'm running Wireshark on a UNIX-flavored OS; why does some network
+ interface on my machine not show up in the list of interfaces in the
+ "Interface:" field in the dialog box popped up by "Capture->Start", and/or
+ why does Wireshark give me an error if I try to capture on that interface?
+
+ A: You may need to run Wireshark from an account with sufficient privileges
+ to capture packets, such as the super-user account, or may need to give your
+ account sufficient privileges to capture packets. Only those interfaces that
+ Wireshark can open for capturing show up in that list; if you don't have
+ sufficient privileges to capture on any interfaces, no interfaces will show
+ up in the list. See the Wireshark Wiki item on capture privileges for
+ details on how to give a particular account or account group capture
+ privileges on platforms where that can be done.
+
+ If you are running Wireshark from an account with sufficient privileges,
+ then note that Wireshark relies on the libpcap library, and on the
+ facilities that come with the OS on which it's running in order to do
+ captures. On some OSes, those facilities aren't present by default; see the
+ Wireshark Wiki item on adding capture support for details.
+
+ And, even if you're running with an account that has sufficient privileges
+ to capture, and capture support is present in your OS, if the OS or the
+ libpcap library don't support capturing on a particular network interface
+ device or particular types of devices, Wireshark won't be able to capture on
+ that device.
+
+ On Solaris, note that libpcap 0.6.2 and earlier didn't support Token Ring
+ interfaces; the current version, 0.7.2, does support Token Ring, and the
+ current version of Wireshark works with libcap 0.7.2 and later.
+
+ If an interface doesn't show up in the list of interfaces in the
+ "Interface:" field, and you know the name of the interface, try entering
+ that name in the "Interface:" field and capturing on that device.
+
+ If the attempt to capture on it succeeds, the interface is somehow not being
+ reported by the mechanism Wireshark uses to get a list of interfaces; please
+ report this to wireshark-dev@wireshark.org giving full details of the
+ problem, including
+ * the operating system you're using, and the version of that operating
+ system (for Linux, give both the version number of the kernel and the
+ name and version number of the distribution you're using);
+ * the type of network device you're using.
+
+ If you are having trouble capturing on a particular network interface, and
+ you've made sure that (on platforms that require it) you've arranged that
+ packet capture support is present, as per the above, first try capturing on
+ that device with tcpdump.
+
+ If you can capture on the interface with tcpdump, send mail to
+ wireshark-users@wireshark.org giving full details of the problem, including
+ * the operating system you're using, and the version of that operating
+ system (for Linux, give both the version number of the kernel and the
+ name and version number of the distribution you're using);
+ * the type of network device you're using;
+ * the error message you get from Wireshark.
- A: This is almost certainly a problem with one or more of:
+ If you cannot capture on the interface with tcpdump, this is almost
+ certainly a problem with one or more of:
* the operating system you're using;
* the device driver for the interface you're using;
- * the libpcap/WinPcap library and, if this is Windows, the WinPcap
- device driver;
+ * the libpcap library;
- so:
- * if you are using Windows, see the WinPcap support page (or the
- local mirror of that page) - check the "Submitting bugs" section;
- * if you are using some Linux distribution, some version of BSD, or
- some other UNIX-flavored OS, you should report the problem to the
- company or organization that produces the OS (in the case of a
- Linux distribution, report the problem to whoever produces the
- distribution).
+ so you should report the problem to the company or organization that
+ produces the OS (in the case of a Linux distribution, report the problem to
+ whoever produces the distribution).
- Q 5.18: My machine crashes or resets itself when I select "Start" from
- the "Capture" menu or select "Preferences" from the "Edit" menu.
+ You may also want to ask the wireshark-users@wireshark.org and the
+ tcpdump-workers@tcpdump.org mailing lists to see if anybody happens to know
+ about the problem and know a workaround or fix for the problem. In your
+ mail, please give full details of the problem, as described above, and also
+ indicate that the problem occurs with tcpdump not just with Wireshark.
- A: Both of those operations cause Ethereal to try to build a list of
- the interfaces that it can open; it does so by getting a list of
- interfaces and trying to open them. There is probably an OS, driver,
- or, for Windows, WinPcap bug that causes the system to crash when this
- happens; see the previous question.
+ Q 9.2: I'm running Wireshark on a UNIX-flavored OS; why do no network
+ interfaces show up in the list of interfaces in the "Interface:" field in
+ the dialog box popped up by "Capture->Start"?
- Q 5.19: Does Ethereal work on Windows ME?
+ A: This is really the same question as the previous one; see the response to
+ that question.
- A: Yes, but if you want to capture packets, you will need to install
- the latest version of WinPcap, as 2.02 and earlier versions of WinPcap
- didn't support Windows ME. You should also install the latest version
- of Ethereal as well.
+ Q 9.3: I'm capturing packets on Linux; why do the time stamps have only
+ 100ms resolution, rather than 1us resolution?
- Q 5.20: Does Ethereal work on Windows XP?
+ A: Wireshark gets time stamps from libpcap/WinPcap, and libpcap/WinPcap get
+ them from the OS kernel, so Wireshark - and any other program using libpcap,
+ such as tcpdump - is at the mercy of the time stamping code in the OS for
+ time stamps.
+
+ At least on x86-based machines, Linux can get high-resolution time stamps on
+ newer processors with the Time Stamp Counter (TSC) register; for example,
+ Intel x86 processors, starting with the Pentium Pro, and including all x86
+ processors since then, have had a TSC, and other vendors probably added the
+ TSC at some point to their families of x86 processors.
+
+ The Linux kernel must be configured with the CONFIG_X86_TSC option enabled
+ in order to use the TSC. Make sure this option is enabled in your kernel.
+
+ In addition, some Linux distributions may have bugs in their versions of the
+ kernel that cause packets not to be given high-resolution time stamps even
+ if the TSC is enabled. See, for example, bug 61111 for Red Hat Linux 7.2. If
+ your distribution has a bug such as this, you may have to run a standard
+ kernel from kernel.org in order to get high-resolution time stamps.
+
+10. Capturing packets on wireless LANs
+
+ Q 10.1: How can I capture raw 802.11 frames, including non-data (management,
+ beacon) frames?
+
+ A: That depends on the operating system on which you're running, and on the
+ 802.11 interface on which you're capturing.
+
+ This would probably require that you capture in promiscuous mode or in the
+ mode called "monitor mode" or "RFMON mode". On some platforms, or with some
+ cards, this might require that you capture in monitor mode - promiscuous
+ mode might not be sufficient. If you want to capture traffic on networks
+ other than the one with which you're associated, you will have to capture in
+ monitor mode.
+
+ Not all operating systems support capturing non-data packets and, even on
+ operating systems that do support it, not all drivers, and thus not all
+ interfaces, support it. Even on those that do, monitor mode might not be
+ supported by the operating system or by the drivers for all interfaces.
+
+ NOTE: an interface running in monitor mode will, on most if not all
+ platforms, not be able to act as a regular network interface; putting it
+ into monitor mode will, in effect, take your machine off of whatever network
+ it's on as long as the interface is in monitor mode, allowing it only to
+ passively capture packets.
+
+ This means that you should disable name resolution when capturing in monitor
+ mode; otherwise, when Wireshark (or TShark, or tcpdump) tries to display IP
+ addresses as host names, it will probably block for a long time trying to
+ resolve the name because it will not be able to communicate with any DNS or
+ NIS servers.
+
+ See the Wireshark Wiki item on 802.11 capturing for details.
+
+ Q 10.2: How do I capture on an 802.11 device in monitor mode?
+
+ A: Whether you will be able to capture in monitor mode depends on the
+ operating system, adapter, and driver you're using. See the previous
+ question for information on monitor mode, including a link to the Wireshark
+ Wiki page that gives details on 802.11 capturing.
+
+11. Viewing traffic
+
+ Q 11.1: Why am I seeing lots of packets with incorrect TCP checksums?
+
+ A: If the packets that have incorrect TCP checksums are all being sent by
+ the machine on which Wireshark is running, this is probably because the
+ network interface on which you're capturing does TCP checksum offloading.
+ That means that the TCP checksum is added to the packet by the network
+ interface, not by the OS's TCP/IP stack; when capturing on an interface,
+ packets being sent by the host on which you're capturing are directly handed
+ to the capture interface by the OS, which means that they are handed to the
+ capture interface without a TCP checksum being added to them.
+
+ The only way to prevent this from happening would be to disable TCP checksum
+ offloading, but
+ 1. that might not even be possible on some OSes;
+ 2. that could reduce networking performance significantly.
- A: Yes, but if you want to capture packets, you will need to install
- the latest version of WinPcap, as 2.2 and earlier versions of WinPcap
- didn't support Windows XP.
+ However, you can disable the check that Wireshark does of the TCP checksum,
+ so that it won't report any packets as having TCP checksum errors, and so
+ that it won't refuse to do TCP reassembly due to a packet having an
+ incorrect TCP checksum. That can be set as an Wireshark preference by
+ selecting "Preferences" from the "Edit" menu, opening up the "Protocols"
+ list in the left-hand pane of the "Preferences" dialog box, selecting "TCP",
+ from that list, turning off the "Check the validity of the TCP checksum when
+ possible" option, clicking "Save" if you want to save that setting in your
+ preference file, and clicking "OK".
+
+ It can also be set on the Wireshark or TShark command line with a -o
+ tcp.check_checksum:false command-line flag, or manually set in your
+ preferences file by adding a tcp.check_checksum:false line.
- Q 5.21: Why doesn't Ethereal correctly identify RTP packets? It shows
- them only as UDP.
+ Q 11.2: I've just installed Wireshark, and the traffic on my local LAN is
+ boring. Where can I find more interesting captures?
- A: Ethereal can identify a UDP datagram as containing a packet of a
- particular protocol running atop UDP only if
- 1. The protocol in question has a particular standard port number,
- and the UDP source or destination port number is that port
- 2. Packets of that protocol can be identified by looking for a
- "signature" of some type in the packet - i.e., some data that, if
- Ethereal finds it in some particular part of a packet, means that
- the packet is almost certainly a packet of that type.
- 3. Some other traffic earlier in the capture indicated that, for
- example, UDP traffic between two particular addresses and ports
- will be RTP traffic.
-
- RTP doesn't have a standard port number, so 1) doesn't work; it
- doesn't, as far as I know, have any "signature", so 2) doesn't work.
-
- That leaves 3). If there's RTSP traffic that sets up an RTP session,
- then, at least in some cases, the RTSP dissector will set things up so
- that subsequent RTP traffic will be identified. Currently, that's the
- only place we do that; there may be other places.
-
- However, there will always be places where Ethereal is simply
- incapable of deducing that a given UDP flow is RTP; a mechanism would
- be needed to allow the user to specify that a given conversation
- should be treated as RTP. As of Ethereal 0.8.16, such a mechanism
- exists; if you select a UDP or TCP packet, the right mouse button menu
- will have a "Decode As..." menu item, which will pop up a dialog box
- letting you specify that the source port, the destination port, or
- both the source and destination ports of the packet should be
- dissected as some particular protocol.
-
- Q 5.22: Why doesn't Ethereal show Yahoo Messenger packets in captures
- that contain Yahoo Messenger traffic?
-
- A: Ethereal only recognizes as Yahoo Messenger traffic packets to or
- from TCP port 3050 that begin with "YPNS", "YHOO", or "YMSG". TCP
- segments that start with the middle of a Yahoo Messenger packet that
- takes more than one TCP segment will not be recognized as Yahoo
- Messenger packets (even if the TCP segment also contains the beginning
- of another Yahoo Messenger packet).
-
- Q 5.23: Why do I get the error
-
- Gdk-ERROR **: Palettized display (256-colour) mode not supported on
- Windows.
- aborting....
-
- when I try to run Ethereal on Windows?
-
- A: Ethereal is built using the GTK+ toolkit, which supports most
- UNIX-flavored OSes, and also supports Windows; that toolkit doesn't
- support 256-color mode on Windows - it requires HiColor (16-bit
- colors) or more. If your display supports more than 256 colors, switch
- to a display mode with more colors; if it doesn't support more than
- 256 colors, you will be unable to run Ethereal.
-
- Q 5.24: When I capture on Windows in promiscuous mode, I can see
- packets other than those sent to or from my machine; however, those
- packets show up with a "Short Frame" indication, unlike packets to or
- from my machine. What should I do to arrange that I see those packets
- in their entirety?
-
- A: In at least some cases, this appears to be the result of PGPnet
- running on the network interface on which you're capturing; turn it
- off on that interface.
-
- Q 5.25: How can I capture raw 802.11 packets, including non-data
- (management, beacon) packets?
-
- A: That would require that your 802.11 interface run in the mode
- called "monitor mode" or "RFMON mode". Not all operating systems
- support that and, even on operating systems that do support it, not
- all drivers, and thus not all cards, support it.
-
- Cisco Aironet cards:
-
- The only platforms that allow Ethereal to capture raw 802.11 packets
- on Cisco Aironet cards are:
- * Linux, with a 2.4.6 or later kernel;
- * FreeBSD 4.6 or later, as the driver in FreeBSD 4.5 has bugs that
- cause packets not to be captured correctly, and the driver in
- releases prior to 4.5 didn't support capturing raw packets.
-
- On FreeBSD, the ancontrol utility must be used; do not enable the full
- Aironet header via BPF, as Ethereal doesn't currently support that.
-
- On Linux with the driver in the 2.4.6 through 2.4.19 kernel, you will
- need to do
-
-echo "Mode: rfmon" >/proc/driver/aironet/ethN/Config
-
- if your Aironet card is ethN. To capture traffic from any BSS, do
-
-echo "Mode: y" >/proc/driver/aironet/ethN/Config
-
- and to return to the normal mode, do
-
-echo "Mode: ess" >/proc/driver/aironet/ethN/Config
-
- On Linux with the driver in the 2.4.20 kernel, or with the CVS drivers
- from the airo-linux SourceForge site, you will have to capture on the
- wifiN interface if your Aironet card is ethN, after running the
- commands listed above.
-
- In all of those cases, Ethereal would have to be linked with libpcap
- 0.7.1 or later; this means that most Ethereal binary packages won't
- work unless they're statically linked with libpcap 0.7.1 or later, or
- they're dynamically linked with libpcap and your system has a libpcap
- 0.7.1 or later shared library installed (note that libpcap source
- package from tcpdump.org does not build shared libraries). Some binary
- packaging mechanisms might make it difficult to install Ethereal
- binary packages built to depend on older libpcap binary packages if
- you have a newer libpcap binary package installed; the installer
- programs for those packaging mechanisms might support disabling
- dependency checking so that they will install Ethereal even though a
- newer version of libpcap is installed.
-
- Cards using the Prism II chip set (see this page of Linux 802.11
- information for details on wireless cards, including information on
- the chips they use):
-
- You can capture raw 802.11 packets with Prism II cards on Linux
- systems with the 0.1.14-pre6 or later version of the linux-wlan-ng
- drivers (see the linux-wlan page, and the linux-wlan-ng tarball
- directory).
-
- Those require either Solomon Peachy's patch to libpcap 0.7.1 (see his
- libpcap-0.7.1-prism.diff file, or his RPMs of that version of
- libpcap), or the current CVS version of libpcap, which includes his
- patch (download it from the "Current Tar files" section of the
- tcpdump.org Web site). If you apply his patches to libpcap 0.7.1 and
- rebuild and install libpcap, or if you build and install the current
- CVS version of libpcap, you would have to rebuild Ethereal from
- source, linking it with that new version of libpcap; an Ethereal
- binary package would not work. Ethereal binary packages might work if
- you install the libpcap-0.7.1-1prism.i386.rpm RPM, as it might install
- a libpcap shared library in place of the one on your system.
-
- You may have to run a command to put the interface into monitor mode,
- or to change other interface settings, and you might have to capture
- on a wlanN interface rather than a ethN interface, in order to capture
- raw 802.11 packets. The interface settings are available in your
- wlan-ng.conf file. See the wlan-ng FAQ for additional information.
-
- On other platforms, capturing raw 802.11 packets on Prism II cards is
- not currently supported.
-
- Orinoco Silver and Gold cards:
-
- On Linux systems, there are patches on the Orinoco Monitor Mode Patch
- Page that should allow you to do capture raw 802.11 packets. You will
- have to determine which version of the driver you have, and select the
- appropriate patch.
-
- Note that the page indicates that not all versions of the Orinoco
- firmware support this patch. It says, for some versions of the patch,
- "This patch should allow monitor mode with v8.10 firmware (untested w/
- 8.42);" if you have version 8.10 or later firmware on your Orinoco
- cards, you might have to use those patches, with the corresponding
- versions of the Orinoco driver, in order to run in monitor mode.
-
- That patch is written for the drivers included with the pcmcia-cs
- drivers, but works equally well for the Orinoco drivers provided with
- Linux kernels up to 2.4.20. To apply a patch to your kernel drivers,
- simply copy the orinoco-09b-patch.diff file to the
- /usr/src/linux/drivers/net directory and patch according to the
- directions on the Orinoco Monitor Mode Patch Page. You can double-
- check the version of the Orinoco drivers that shipped with your kernel
- by examining the first few lines of the orinoco.c file.
-
- Te Orinoco patches require either Solomon Peachy's patch to libpcap
- 0.7.1 (see his libpcap-0.7.1-prism.diff file, or his RPMs of that
- version of libpcap), or the current CVS version of libpcap, which
- includes his patch (download it from the "Current Tar files" section
- of the tcpdump.org Web site). If you apply his patches to libpcap
- 0.7.1 and rebuild and install libpcap, or if you build and install the
- current CVS version of libpcap, you would have to rebuild Ethereal
- from source, linking it with that new version of libpcap; an Ethereal
- binary package would not work. Ethereal binary packages might work if
- you install the libpcap-0.7.1-1prism.i386.rpm RPM, as it might install
- a libpcap shared library in place of the one on your system.
-
- On other platforms, capturing raw 802.11 packets on Orinoco cards is
- not currently supported.
-
- Other 802.11 interfaces:
-
- With other 802.11 interfaces, no platform allows Ethereal to capture
- raw 802.11 packets, as far as we know. If you know of other 802.11
- interfaces that are supported (note that there are many "Prism II
- cards", so your card might be a Prism II card), please let us know,
- and include URLs for sites containing any necessary patches to add
- this support.
-
- On platforms that don't allow Ethereal to capture raw 802.11 packets,
- the 802.11 network will appear like an Ethernet to Ethereal.
-
- Q 5.26: How can I capture packets with CRC errors?
-
- A: Ethereal can capture only the packets that the packet capture
- library - libpcap on UNIX-flavored OSes, and the WinPcap port to
- Windows of libpcap on Windows - can capture, and libpcap/WinPcap can
- capture only the packets that the OS's raw packet capture mechanism
- (or the WinPcap driver, and the underlying OS networking code and
- network interface drivers, on Windows) will allow it to capture.
-
- Unless the OS can be configured to supply packets with errors such as
- invalid CRCs to the raw packet capture mechanism, Ethereal - and other
- programs that capture raw packets, such as tcpdump - cannot capture
- those packets. You will have to determine whether your OS can be so
- configured, configure it if possible, and make whatever changes to
- libpcap and the packet capture program you're using are necessary to
- support capturing those packets.
-
- Q 5.27: How can I capture entire frames, including the FCS?
-
- A: Ethereal can't capture any data that the packet capture library -
- libpcap on UNIX-flavored OSes, and the WinPcap port to Windows of
- libpcap on Windows - can capture, and libpcap/WinPcap can capture only
- the data that the OS's raw packet capture mechanism (or the WinPcap
- driver, and the underlying OS networking code and network interface
- drivers, on Windows) will allow it to capture.
-
- For any particular link-layer network type, unless the OS supplies the
- FCS of a frame as part of the frame, or can be configured to supply
- the FCS of a frame as part of the frame, Ethereal - and other programs
- that capture raw packets, such as tcpdump - cannot capture the FCS of
- a frame. You will have to determine whether your OS can be so
- configured, configure it if possible, and make whatever changes to
- libpcap and the packet capture program you're using are necessary to
- support capturing the FCS of a frame. Most if not all OSes probably do
- not support capturing the FCS of a frame on Ethernet, and probably do
- not support it on most other link-layer types.
-
- Q 5.28: Ethereal hangs after I stop a capture.
-
- A: The most likely reason for this is that Ethereal is trying to look
- up an IP address in the capture to convert it to a name (so that, for
- example, it can display the name in the source address or destination
- address columns), and that lookup process is taking a very long time.
-
- Ethereal calls a routine in the OS of the machine on which it's
- running to convert of IP addresses to the corresponding names. That
- routine probably does one or more of:
- * a search of a system file listing IP addresses and names;
- * a lookup using DNS;
- * on UNIX systems, a lookup using NIS;
- * on Windows systems, a NetBIOS-over-TCP query.
+ A: We have a collection of strange and exotic sample capture files at
+ http://wiki.wireshark.org/SampleCaptures
- If a DNS server that's used in an address lookup is not responding,
- the lookup will fail, but will only fail after a timeout while the
- system routine waits for a reply.
-
- In addition, on Windows systems, if the DNS lookup of the address
- fails, either because the server isn't responding or because there are
- no records in the DNS that could be used to map the address to a name,
- a NetBIOS-over-TCP query will be made. That query involves sending a
- message to the NetBIOS-over-TCP name service on that machine, asking
- for the name and other information about the machine. If the machine
- isn't running software that responds to those queries - for example,
- many non-Windows machines wouldn't be running that software - the
- lookup will only fail after a timeout. Those timeouts can cause the
- lookup to take a long time.
-
- If you disable network address-to-name translation - for example, by
- turning off the "Enable network name resolution" option in the "Name
- resolution" options in the dialog box you get by selecting
- "Preferences" from the "Edit" menu - the lookups of the address won't
- be done, which may speed up the process of reading the capture file
- after the capture is stopped. You can make that setting the default by
- using the "Save" button in that dialog box; note that this will save
- all your current preference settings.
-
- If Ethereal hangs when reading a capture even with network name
- resolution turned off, there might, for example, be a bug in one of
- Ethereal's dissectors for a protocol causing it to loop infinitely.
- The bug should be reported to the Ethereal developers' mailing list at
- ethereal-dev@ethereal.com.
-
- On UNIX-flavored OSes, please try to force Ethereal to dump core, by
- sending it a SIGABRT signal (usually signal 6) with the kill command,
- and then get a stack trace if you have a debugger installed. A stack
- trace can be obtained by using your debugger (gdb in this example),
- the Ethereal binary, and the resulting core file. Here's an example of
- how to use the gdb command backtrace to do so.
- $ gdb ethereal core
- (gdb) backtrace
- ..... prints the stack trace
- (gdb) quit
- $
+ Q 11.3: Why doesn't Wireshark correctly identify RTP packets? It shows them
+ only as UDP.
- The core dump file may be named "ethereal.core" rather than "core" on
- some platforms (e.g., BSD systems)
-
- Also, if at all possible, please send a copy of the capture file that
- caused the problem; when capturing packets, Ethereal normally writes
- captured packets to a temporary file, which will probably be in /tmp
- or /var/tmp on UNIX-flavored OSes and \TEMP on Windows, so the capture
- file will probably be there. It will have a name beginning with ether,
- with some mixture of letters and numbers after that. Please don't send
- a trace file greater than 1 MB when compressed. If the trace file
- contains sensitive information (e.g., passwords), then please do not
- send it.
-
- Q 5.29: How can I search for, or filter, packets that have a
- particular string anywhere in them?
-
- A: Currently, you can't.
-
- That's a feature that would be hard to implement in capture filters
- without changes to the capture filter code, which, on many platforms,
- is in the OS kernel and, on other platforms, is in the libpcap
- library.
-
- It would be easier to implement in display filters, but it hasn't been
- implemented yet. It would be best implemented as a display filter
- "string match" operator, which would let you check not only the entire
- packet for a string, but check portions of the packet for a string. It
- should probably not use a naive string matching mechanism, as there
- are mechanisms much faster than the naive one.
-
-
- Support can be found on the ethereal-users[AT]ethereal.com mailing
- list.
- For corrections/additions/suggestions for this page, please send email
- to: ethereal-web[AT]ethereal.com
- Last modified: Thu, March 20 2003.
+ A: Wireshark can identify a UDP datagram as containing a packet of a
+ particular protocol running atop UDP only if
+ 1. The protocol in question has a particular standard port number, and the
+ UDP source or destination port number is that port
+ 2. Packets of that protocol can be identified by looking for a "signature"
+ of some type in the packet - i.e., some data that, if Wireshark finds it
+ in some particular part of a packet, means that the packet is almost
+ certainly a packet of that type.
+ 3. Some other traffic earlier in the capture indicated that, for example,
+ UDP traffic between two particular addresses and ports will be RTP
+ traffic.
+
+ RTP doesn't have a standard port number, so 1) doesn't work; it doesn't, as
+ far as I know, have any "signature", so 2) doesn't work.
+
+ That leaves 3). If there's RTSP traffic that sets up an RTP session, then,
+ at least in some cases, the RTSP dissector will set things up so that
+ subsequent RTP traffic will be identified. Currently, that's the only place
+ we do that; there may be other places.
+
+ However, there will always be places where Wireshark is simply incapable of
+ deducing that a given UDP flow is RTP; a mechanism would be needed to allow
+ the user to specify that a given conversation should be treated as RTP. As
+ of Wireshark 0.8.16, such a mechanism exists; if you select a UDP or TCP
+ packet, the right mouse button menu will have a "Decode As..." menu item,
+ which will pop up a dialog box letting you specify that the source port, the
+ destination port, or both the source and destination ports of the packet
+ should be dissected as some particular protocol.
+
+ Q 11.4: Why doesn't Wireshark show Yahoo Messenger packets in captures that
+ contain Yahoo Messenger traffic?
+
+ A: Wireshark only recognizes as Yahoo Messenger traffic packets to or from
+ TCP port 3050 that begin with "YPNS", "YHOO", or "YMSG". TCP segments that
+ start with the middle of a Yahoo Messenger packet that takes more than one
+ TCP segment will not be recognized as Yahoo Messenger packets (even if the
+ TCP segment also contains the beginning of another Yahoo Messenger packet).
+
+12. Filtering traffic
+
+ Q 12.1: I saved a filter and tried to use its name to filter the display;
+ why do I get an "Unexpected end of filter string" error?
+
+ A: You cannot use the name of a saved display filter as a filter. To filter
+ the display, you can enter a display filter expression - not the name of a
+ saved display filter - in the "Filter:" box at the bottom of the display,
+ and type the key or press the "Apply" button (that does not require you to
+ have a saved filter), or, if you want to use a saved filter, you can press
+ the "Filter:" button, select the filter in the dialog box that pops up, and
+ press the "OK" button.
+
+ Q 12.2: How can I search for, or filter, packets that have a particular
+ string anywhere in them?
+
+ A: If you want to do this when capturing, you can't. That's a feature that
+ would be hard to implement in capture filters without changes to the capture
+ filter code, which, on many platforms, is in the OS kernel and, on other
+ platforms, is in the libpcap library.
+
+ In releases prior to 0.9.14, you also can't search for, or filter, packets
+ containing a particular string even after you've captured them.
+
+ In 0.9.14, you can search for, but not filter, packets that have a
+ particular string; this has been added to the "Find Frame" dialog ("Find
+ Frame" under the "Edit" menu, or control-F).
+
+ In 0.9.15 and later, you can search for those packets using either the
+ mechanism introduced in 0.9.14 or using the new "contains" operator in
+ filter expressions, which lets you search the entire packet or text string
+ or byte string fields in the packet; the "contains" operator can also be
+ used in expressions used to filter the display.
+
+ Q 12.3: How do I filter a capture to see traffic for virus XXX?
+
+ A: For some viruses/worms there might be a capture filter to recognize the
+ virus traffic. Check the CaptureFilters page on the Wireshark Wiki to see if
+ anybody's added such a filter.
+
+ Note that Wireshark was not designed to be an intrusion detection system;
+ you might be able to use it as an IDS, but in most cases software designed
+ to be an IDS, such as Snort or Prelude, will probably work better.
+
+ The Bleeding Edge of Snort has a collection of signatures for Snort to
+ detect various viruses, worms, and the like.
git.samba.org / obnox / wireshark / wip.git / blobdiff