4 Note: This is just an ASCII snapshot of the faq and may not be up to
5 date. Please go to http://www.ethereal.com/faq for the up to
6 date version. The version of this snapshot can be found at the
13 1.1 Where can I get help?
15 1.2 What protocols are currently supported?
17 1.3 Are there any plans to support {your favorite protocol}?
19 1.4 Can Ethereal read capture files from {your favorite network
22 1.5 What devices can Ethereal use to capture packets?
24 1.6 How do you pronounce Ethereal? Where did the name come from?
28 2.1 I downloaded the Win32 installer, but when I try to run it, I get
31 2.2 When I try to download the WinPcap driver and library, I can't get
32 to the WinPcap Web site.
36 3.1 I installed an Ethereal RPM, but Ethereal doesn't seem to be
37 installed; only Tethereal is installed.
41 4.1 The configure script can't find pcap.h or bpf.h, but I have
44 4.2 Why do I get the error
46 dftest_DEPENDENCIES was already defined in condition TRUE, which
47 implies condition HAVE_PLUGINS_TRUE
49 when I try to build Ethereal from CVS or a CVS snapshot?
51 4.3 The link fails with a number of "Output line too long." messages
52 followed by linker errors.
54 4.4 The link fails on Solaris because plugin_list is undefined.
56 4.5 The build fails on Windows because of conflicts between winsock.h
59 4.6 I'm trying to build Ethereal 0.10.0a on Windows; why is the the
60 build failing with an error saying it can't find "Makefile.nmake"?
64 5.1 When I use Ethereal to capture packets, I see only packets to and
65 from my machine, or I'm not seeing all the traffic I'm expecting to
66 see from or to the machine I'm trying to monitor.
68 5.2 I can't see any TCP packets other than packets to and from my
69 machine, even though another analyzer on the network sees those
72 5.3 I'm only seeing ARP packets when I try to capture traffic.
74 5.4 I'm running Ethereal on Windows; why does some network interface
75 on my machine not show up in the list of interfaces in the
76 "Interface:" field in the dialog box popped up by "Capture->Start",
77 and/or why does Ethereal give me an error if I try to capture on that
80 5.5 I'm running Ethereal on Windows; why do no network interfaces show
81 up in the list of interfaces in the "Interface:" field in the dialog
82 box popped up by "Capture->Start"?
84 5.6 I'm running Ethereal on Windows; why doesn't my serial port/ADSL
85 modem/ISDN modem/show up in the list of interfaces in the "Interface:"
86 field in the dialog box popped up by "Capture->Start"?
88 5.7 I'm running Ethereal on a UNIX-flavored OS; why does some network
89 interface on my machine not show up in the list of interfaces in the
90 "Interface:" field in the dialog box popped up by "Capture->Start",
91 and/or why does Ethereal give me an error if I try to capture on that
94 5.8 I'm running Ethereal on a UNIX-flavored OS; why do no network
95 interfaces show up in the list of interfaces in the "Interface:" field
96 in the dialog box popped up by "Capture->Start"?
98 5.9 Can Ethereal capture on (my T1/E1 line, SS7 links, etc.)?
100 5.10 How do I put an interface into promiscuous mode?
102 5.11 I can set a display filter just fine, but capture filters don't
105 5.12 I'm entering valid capture filters, but I still get "parse error"
108 5.13 I saved a filter and tried to use its name to filter the display,
109 but I got an "Unexpected end of filter string" error.
111 5.14 Why am I seeing lots of packets with incorrect TCP checksums?
113 5.15 I've just installed Ethereal, and the traffic on my local LAN is
116 5.16 When I run Ethereal on Solaris 8, it dies with a Bus Error when I
119 5.17 When I run Tethereal with the "-x" option, it crashes with an
120 error "** ERROR **: file print.c: line 691 (print_line): should not be
123 5.18 When I run Ethereal on Windows NT, it dies with a Dr. Watson
124 error, reporting an "Integer division by zero" exception, when I start
127 5.19 When I try to run Ethereal, it complains about
128 sprint_realloc_objid being undefined.
130 5.20 I'm running Ethereal on Linux; why do my time stamps have only
131 100ms resolution, rather than 1us resolution?
133 5.21 I'm capturing packets on {Windows 95, Windows 98, Windows Me};
134 why are the time stamps on packets wrong?
136 5.22 When I try to run Ethereal on Windows, it fails to run because it
137 can't find packet.dll.
139 5.23 I'm running Ethereal on Windows NT/2000/XP/Server; my machine has
140 a PPP (dial-up POTS, ISDN, etc.) interface, and it shows up in the
141 "Interface" item in the "Capture Options" dialog box. Why can no
142 packets be sent on or received from that network while I'm trying to
143 capture traffic on that interface?
145 5.24 I'm running Ethereal on Windows 95/98/Me, on a machine with more
146 than one network adapter of the same type; Ethereal shows all of those
147 adapters with the same name, but I can't use any of those adapters
148 other than the first one.
150 5.25 I'm running Ethereal on Windows, and I'm not seeing any traffic
151 being sent by the machine running Ethereal.
153 5.26 I'm trying to capture traffic but I'm not seeing any.
155 5.27 I have an XXX network card on my machine; if I try to capture on
156 it, my machine crashes or resets itself.
158 5.28 My machine crashes or resets itself when I select "Start" from
159 the "Capture" menu or select "Preferences" from the "Edit" menu.
161 5.29 Does Ethereal work on Windows Me?
163 5.30 Does Ethereal work on Windows XP?
165 5.31 Why doesn't Ethereal correctly identify RTP packets? It shows
168 5.32 Why doesn't Ethereal show Yahoo Messenger packets in captures
169 that contain Yahoo Messenger traffic?
171 5.33 Why do I get the error
173 Gdk-ERROR **: Palettized display (256-colour) mode not supported on
177 when I try to run Ethereal on Windows?
179 5.34 When I capture on Windows in promiscuous mode, I can see packets
180 other than those sent to or from my machine; however, those packets
181 show up with a "Short Frame" indication, unlike packets to or from my
182 machine. What should I do to arrange that I see those packets in their
185 5.35 I'm capturing packets on a machine on a VLAN; why don't the
186 packets I'm capturing have VLAN tags?
188 5.36 How can I capture raw 802.11 packets, including non-data
189 (management, beacon) packets?
191 5.37 I'm trying to capture 802.11 traffic on Windows; why am I not
194 5.38 I'm trying to capture 802.11 traffic on Windows; why am I seeing
195 packets received by the machine on which I'm capturing traffic, but
196 not packets sent by that machine?
198 5.39 How can I capture packets with CRC errors?
200 5.40 How can I capture entire frames, including the FCS?
202 5.41 Ethereal hangs after I stop a capture.
204 5.42 How can I search for, or filter, packets that have a particular
205 string anywhere in them?
208 Q 1.1: Where can I get help?
210 A: Support is available on the ethereal-users mailing list.
211 Subscription information and archives for all of Ethereal's mailing
212 lists can be found at http://www.ethereal.com/lists
214 Q 1.2: What protocols are currently supported?
216 A: There are currently 442 supported protocols and media, listed
217 below. Descriptions can be found in the ethereal(1) man page.
220 802.1x Authentication
221 AAL type 2 signalling protocol - Capability set 1 (Q.2630.1)
222 AFS (4.0) Replication Server call declarations
225 ANSI IS-637-A (SMS) Teleservice Layer
226 ANSI IS-637-A (SMS) Transport Layer
227 ANSI IS-683-A (OTA (Mobile))
228 ANSI Mobile Application Part
229 AOL Instant Messenger
236 AVS WLAN Capture header
237 Ad hoc On-demand Distance Vector Routing Protocol
238 Address Resolution Protocol
239 Aggregate Server Access Protocol
241 Alteon - Transparent Proxy Cache Protocol
242 Andrew File System (AFS)
243 Apache JServ Protocol v1.3
244 AppleTalk Filing Protocol
245 AppleTalk Session Protocol
246 AppleTalk Transaction Protocol packet
247 Appletalk Address Resolution Protocol
248 Application Configuration Access Protocol
249 Async data over ISDN (V.120)
250 Authentication Header
251 BACnet Virtual Link Control
256 Banyan Vines Fragmentation Protocol
263 Bearer Independent Call Control
264 Bi-directional Fault Detection Control Message
265 Blocks Extensible Exchange Protocol
269 Border Gateway Protocol
270 Building Automation and Control Network APDU
271 Building Automation and Control Network NPDU
273 CDS Clerk Server Calls
274 Check Point High Availability Protocol
277 Cisco Discovery Protocol
278 Cisco Group Management Protocol
280 Cisco Hot Standby Router Protocol
282 Cisco Interior Gateway Routing Protocol
286 CoSine IPNOS L2 debug output
287 Common Open Policy Service
288 Common Unix Printing System (CUPS) Browsing Protocol
289 Connectionless Lightweight Directory Access Protocol
290 Cross Point Frame Injector
292 DCE Distributed Time Service Local Server
293 DCE Distributed Time Service Provider
296 DCE Security ID Mapper
300 DCE/RPC CDS Solicitation
301 DCE/RPC Conversation Manager
302 DCE/RPC Endpoint Mapper
303 DCE/RPC Endpoint Mapper4
305 DCE/RPC FLDB UBIK TRANSFER
306 DCE/RPC FLDB UBIKVOTE
314 DCE/RPC Remote Management
315 DCE/RPC Repserver Calls
316 DCE/RPC TokenServer Calls
319 DCOM Remote Activation
320 DEC Spanning Tree Protocol
322 DNS Control Program Server
325 Data Stream Interface
326 Datagram Delivery Protocol
328 Distance Vector Multicast Routing Protocol
329 Distcc Distributed Compiler
330 Distributed Checksum Clearinghouse Prototocl
332 Dynamic DNS Tools Protocol
334 Encapsulating Security Payload
335 Enhanced Interior Gateway Routing Protocol
336 EtherNet/IP (Industrial Protocol)
339 Extensible Authentication Protocol
341 FC Fabric Configuration Server
345 Fiber Distributed Data Interface
347 Fibre Channel Common Transport
348 Fibre Channel Fabric Zone Server
349 Fibre Channel Name Server
350 Fibre Channel Protocol for SCSI
352 Fibre Channel Security Protocol
353 Fibre Channel Single Byte Command
354 File Transfer Protocol (FTP)
355 Financial Information eXchange Protocol
358 GARP Multicast Registration Protocol
359 GARP VLAN Registration Protocol
361 GPRS Tunneling Protocol
365 GSM Mobile Application Part
366 GSM SMS TPDU (GSM 03.40)
367 General Inter-ORB Protocol
368 Generic Routing Encapsulation
369 Generic Security Service Application Program Interface
374 HP Extended Local-Link Control
375 HP Remote Maintenance Protocol
376 Hummingbird NFS Daemon
378 Hypertext Transfer Protocol
380 IEEE 802.11 wireless LAN
381 IEEE 802.11 wireless LAN management frame
384 IP Payload Compression
386 IPX Routing Information Protocol
389 ISDN Q.921-User Adaptation Layer
391 ISO 10589 ISIS InTRA Domain Routeing Information Exchange Protocol
392 ISO 8073 COTP Connection-Oriented Transport Protocol
393 ISO 8327-1 OSI Session Protocol
394 ISO 8473 CLNP ConnectionLess Network Protocol
395 ISO 8602 CLTP ConnectionLess Transport Protocol
396 ISO 9542 ESIS Routeing Information Exchange Protocol
397 ITU-T Recommendation H.261
398 ITU-T Recommendation H.263 RTP Payload header (RFC2190)
401 Intelligent Platform Management Interface
402 Inter-Access-Point Protocol
404 Internet Cache Protocol
405 Internet Content Adaptation Protocol
406 Internet Control Message Protocol
407 Internet Control Message Protocol v6
408 Internet Group Management Protocol
409 Internet Group membership Authentication Protocol
410 Internet Message Access Protocol
411 Internet Printing Protocol
413 Internet Protocol Version 6
415 Internet Security Association and Key Management Protocol
416 Internetwork Packet eXchange
421 Kerberos Administration
424 LWAPP Encapsulated Packet
426 Label Distribution Protocol
428 Layer 2 Tunneling Protocol
429 Lightweight Directory Access Protocol
430 Line Printer Daemon Protocol
431 Link Access Procedure Balanced (LAPB)
432 Link Access Procedure Balanced Ethernet (LAPBETHER)
433 Link Access Procedure, Channel D (LAPD)
434 Link Aggregation Control Protocol
435 Link Management Protocol (LMP)
436 Linux cooked-mode capture
437 Local Management Interface
438 LocalTalk Link Access Protocol
440 Lucent/Ascend debug output
442 MMS Message Encapsulation
445 MSN Messenger Service
446 MSNIP: Multicast Source Notification of Interest Protocol
447 MTP 2 Transparent Proxy
448 MTP 2 User Adaptation Layer
449 MTP 3 User Adaptation Layer
450 MTP2 Peer Adaptation Layer
451 Message Transfer Part Level 2
452 Message Transfer Part Level 3
453 Message Transfer Part Level 3 Management
454 Microsoft Directory Replication Service
455 Microsoft Distributed File System
456 Microsoft Exchange MAPI
457 Microsoft Local Security Architecture
458 Microsoft Local Security Architecture (Directory Services)
459 Microsoft Messenger Service
460 Microsoft Network Logon
462 Microsoft Security Account Manager
463 Microsoft Server Service
464 Microsoft Service Control
465 Microsoft Spool Subsystem
466 Microsoft Task Scheduler Service
467 Microsoft Telephony API Service
468 Microsoft Windows Browser Protocol
469 Microsoft Windows Lanman Remote API Protocol
470 Microsoft Windows Logon Protocol
471 Microsoft Workstation Service
476 MultiProtocol Label Switching Header
477 Multicast Router DISCovery protocol
478 Multicast Source Discovery Protocol
485 NTLM Secure Service Provider
486 Name Binding Protocol
487 Name Management Protocol over IPX
489 NetBIOS Datagram Service
491 NetBIOS Session Service
493 NetWare Core Protocol
494 NetWare Link Services Protocol
495 Network Data Management Protocol
497 Network Lock Manager Protocol
498 Network News Transfer Protocol
499 Network Status Monitor CallBack Protocol
500 Network Status Monitor Protocol
501 Network Time Protocol
503 Novell Distributed Print System
505 Open Shortest Path First
506 OpenBSD Encapsulating device
507 OpenBSD Packet Filter log file
508 OpenBSD Packet Filter log file, pre 3.4
510 PPP Bandwidth Allocation Control Protocol
511 PPP Bandwidth Allocation Protocol
512 PPP CDP Control Protocol
513 PPP Callback Control Protocol
514 PPP Challenge Handshake Authentication Protocol
515 PPP Compressed Datagram
516 PPP Compression Control Protocol
517 PPP IP Control Protocol
518 PPP IPv6 Control Protocol
519 PPP Link Control Protocol
520 PPP MPLS Control Protocol
521 PPP Multilink Protocol
523 PPP Password Authentication Protocol
525 PPP-over-Ethernet Discovery
526 PPP-over-Ethernet Session
527 PPPMux Control Protocol
528 Packed Encoding Rules (ASN.1 X.691)
529 Point-to-Point Protocol
530 Point-to-Point Tunnelling Protocol
533 Pragmatic General Multicast
535 Privilege Server operations
536 Protocol Independent Multicast
540 Quake II Network Protocol
541 Quake III Arena Network Protocol
542 Quake Network Protocol
543 QuakeWorld Network Protocol
544 Qualified Logical Link Control
549 RS Interface properties
551 RSYNC File Synchroniser
553 Radio Access Network Application Part
556 Real Time Streaming Protocol
557 Real-Time Transport Protocol
558 Real-time Transport Control Protocol
559 Registry Server Attributes Manipulation Interface
560 Registry server administration operations.
561 Remote Management Control Protocol
562 Remote Override interface
563 Remote Procedure Call
569 Remote sec_login preauth interface.
570 Resource ReserVation Protocol (RSVP)
572 Routing Information Protocol
573 Routing Table Maintenance Protocol
576 SEBEK - Kernel Data Capture
578 SMB (Server Message Block Protocol)
579 SMB MailSlot Protocol
582 SNMP Multiplex Protocol
585 SS7 SCCP-User Adaptation Layer
589 Sequenced Packet eXchange
590 Service Advertisement Protocol
591 Service Location Protocol
592 Session Announcement Protocol
593 Session Description Protocol
594 Session Initiation Protocol
595 Session Initiation Protocol (SIP as raw text)
596 Short Message Peer to Peer
597 Signalling Connection Control Part
598 Signalling Connection Control Part Management
599 Simple Mail Transfer Protocol
600 Simple Network Management Protocol
601 Simple Traversal of UDP Through NAT
603 Skinny Client Control Protocol
604 SliMP3 Communication Protocol
606 Spanning Tree Protocol
608 Stream Control Transmission Protocol
609 Synchronous Data Link Control (SDLC)
611 Systems Network Architecture
612 Systems Network Architecture XID
616 TEREDO Tunneling IPv6 over UDP through NATs
619 Tazmen Sniffer Protocol
622 Time Synchronization Protocol
624 Token-Ring Media Access Control
625 Transaction Capabilities Application Part
626 Transmission Control Protocol
627 Transparent Network Substrate Protocol
628 Trivial File Transfer Protocol
629 UDP Encapsulation of IPsec Packets
630 Universal Computer Protocol
631 User Datagram Protocol
632 Virtual Router Redundancy Protocol
633 Virtual Trunking Protocol
635 Web Cache Coordination Protocol
636 Wellfleet Breath of Life
637 Wellfleet Compression
641 Wireless Session Protocol
642 Wireless Transaction Protocol
643 Wireless Transport Layer Security
644 X Display Manager Control Protocol
650 Yahoo Messenger Protocol
651 Yahoo YMSG Messenger Protocol
655 Yellow Pages Transfer
657 Zone Information Protocol
662 Q 1.3: Are there any plans to support {your favorite protocol}?
664 A: Support for particular protocols is added to Ethereal as a result
665 of people contributing that support; no formal plans for adding
666 support for particular protocols in particular future releases exist.
668 Q 1.4: Can Ethereal read capture files from {your favorite network
671 A: Support for particular protocols is added to Ethereal as a result
672 of people contributing that support; no formal plans for adding
673 support for particular protocols in particular future releases exist.
675 If a network analyzer writes out files in a format already supported
676 by Ethereal (e.g., in libpcap format), Ethereal may already be able to
677 read them, unless the analyzer has added its own proprietary
678 extensions to that format.
680 If a network analyzer writes out files in its own format, or has added
681 proprietary extensions to another format, in order to make Ethereal
682 read captures from that network analyzer, we would either have to have
683 a specification for the file format, or the extensions, sufficient to
684 give us enough information to read the parts of the file relevant to
685 Ethereal, or would need at least one capture file in that format AND a
686 detailed textual analysis of the packets in that capture file (showing
687 packet time stamps, packet lengths, and the top-level packet header)
688 in order to reverse-engineer the file format.
690 Note that there is no guarantee that we will be able to
691 reverse-engineer a capture file format.
693 Q 1.5: What devices can Ethereal use to capture packets?
695 A: Ethereal can read live data from Ethernet, Token-Ring, FDDI, serial
696 (PPP and SLIP) (if the OS on which it's running allows Ethereal to do
697 so), 802.11 wireless LAN (if the OS on which it's running allows
698 Ethereal to do so), ATM connections (if the OS on which it's running
699 allows Ethereal to do so), and the "any" device supported on Linux by
700 recent versions of libpcap. See the list of supported capture media on
701 various OSes for details (several items in there say "Unknown", which
702 doesn't mean "Ethereal can't capture on them", it means "we don't know
703 whether it can capture on them"; we expect that it will be able to
704 capture on many of them, but we haven't tried it ourselves - if you
705 try one of those types and it works, please send an update to
706 ethereal-web[AT]ethereal.com).
708 It can also read a variety of capture file formats, including:
711 * Shomiti/Finisar Surveyor
713 * DOS-based Sniffer (compressed and uncompressed)
716 * NetXray and Windows-based Sniffer
717 * EtherPeek/TokenPeek/AiroPeek
718 * RADCOM WAN/LAN analyzer
719 * Lucent/Ascend debug output
720 * Toshiba ISDN router "snoop" output
722 * ISDN4BSD "i4btrace" utility.
724 * pppd log files (pppdump format)
727 * Visual Networks' Visual UpTime
730 so that it can read traces from various network types, as captured by
731 other applications or equipment, even if it cannot itself capture on
734 Q 1.6: How do you pronounce Ethereal? Where did the name come from?
736 A: The English pronunciation can be found in Merriam-Webster's online
738 http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=ethereal.
740 According to the book "Computer Networks" by Andrew Tannenbaum,
741 Ethernet was named after the "luminiferous ether" which was once
742 thought to carry electromagnetic radiation. Taking that into
743 consideration, Ethereal seemed like an appropriate name for an
747 Q 2.1: I downloaded the Win32 installer, but when I try to run it, I
750 A: The program you used to download it may have downloaded it
751 incorrectly. Web browsers sometimes may do this.
753 Try downloading it with, for example:
754 * Wget, for which Windows binaries are available on the SunSITE FTP
755 server at sunsite.tk or Heiko Herold's windows wget spot - wGetGUI
756 offers a GUI interface that uses wget;
757 * WS_FTP from Ipswitch,
758 * the ftp command that comes with Windows.
760 If you use the ftp command, make sure you do the transfer in binary
761 mode rather than ASCII mode, by using the binary command before
762 transferring the file.
764 Q 2.2: When I try to download the WinPcap driver and library, I can't
765 get to the WinPcap Web site.
767 A: As is the case with all Web sites, that site won't necessarily
768 always be accessible; the server may be down due to a problem or down
769 for maintenance, or there may be a networking problem between you and
770 the server. You should try again later, or try the local mirror or the
771 Wiretapped.net mirror.
774 Q 3.1: I installed an Ethereal RPM, but Ethereal doesn't seem to be
775 installed; only Tethereal is installed.
777 A: Older versions of the Red Hat RPMs for Ethereal put only the
778 non-GUI components into the ethereal RPM, the fact that Ethereal is a
779 GUI program nonwithstanding; newer versions make it a bit clearer by
780 giving that RPM a name starting with ethereal-base.
782 In those older versions, there's a separate ethereal-gnome RPM that
783 includes GUI components such as Ethereal itself, the fact that
784 Ethereal doesn't use GNOME nonwithstanding; newer versions make it a
785 bit clearer by giving that RPM a name starting with ethereal-gtk+.
787 Find the ethereal-gnome or ethereal-gtk+ RPM, and install that also.
790 Q 4.1: The configure script can't find pcap.h or bpf.h, but I have
793 A: Are you sure pcap.h and bpf.h are installed? The official
794 distribution of libpcap only installs the libpcap.a library file when
795 "make install" is run. To install pcap.h and bpf.h, you must run "make
796 install-incl". If you're running Debian or Redhat, make sure you have
797 the "libpcap-dev" or "libpcap-devel" packages installed.
799 It's also possible that pcap.h and bpf.h have been installed in a
800 strange location. If this is the case, you may have to tweak
803 Q 4.2: Why do I get the error
805 dftest_DEPENDENCIES was already defined in condition TRUE, which
806 implies condition HAVE_PLUGINS_TRUE
808 when I try to build Ethereal from CVS or a CVS snapshot?
810 A: You probably have automake 1.5 installed on your machine (the
811 command automake --version will report the version of automake on your
812 machine). There is a bug in that version of automake that causes this
813 problem; upgrade to a later version of automake (1.6 or later).
815 Q 4.3: The link fails with a number of "Output line too long."
816 messages followed by linker errors.
818 A: The version of the sed command on your system is incapable of
819 handling very long lines. On Solaris, for example, /usr/bin/sed has a
820 line length limit too low to allow libtool to work; /usr/xpg4/bin/sed
821 can handle it, as can GNU sed if you have it installed.
823 On Solaris, changing your command search path to search /usr/xpg4/bin
824 before /usr/bin should make the problem go away; on any platform on
825 which you have this problem, installing GNU sed and changing your
826 command path to search the directory in which it is installed before
827 searching the directory with the version of sed that came with the OS
828 should make the problem go away.
830 Q 4.4: The link fails on Solaris because plugin_list is undefined.
832 A: This appears to be due to a problem with some versions of the GTK+
833 and GLib packages from www.sunfreeware.org; un-install those packages,
834 and try getting the 1.2.10 versions from that site, or the versions
835 from The Written Word, or the versions from Sun's GNOME distribution,
836 or the versions from the supplemental software CD that comes with the
837 Solaris media kit, or build them from source from the GTK Web site.
838 Then re-run the configuration script, and try rebuilding Ethereal. (If
839 you get the 1.2.10 versions from www.sunfreeware.org, and the problem
840 persists, un-install them and try installing one of the other versions
843 Q 4.5: The build fails on Windows because of conflicts between
844 winsock.h and winsock2.h.
846 A: As of Ethereal 0.9.5, you must install WinPcap 2.3 or later, and
847 the corresponding version of the developer's pack, in order to be able
848 to compile Ethereal; it will not compile with older versions of the
849 developer's pack. The symptoms of this failure are conflicts between
850 definitions in winsock.h and in winsock2.h; Ethereal uses winsock2.h,
851 but pre-2.3 versions of the WinPcap developer's packet use winsock.h.
852 (2.3 uses winsock2.h, so if Ethereal were to use winsock.h, it would
853 not be able to build with current versions of the WinPcap developer's
856 Note that the installed version of the developer's pack should be the
857 same version as the version of WinPcap you have installed.
859 Q 4.6: I'm trying to build Ethereal 0.10.0a on Windows; why is the the
860 build failing with an error saying it can't find "Makefile.nmake"?
862 A: There was a bug in the 0.10.0a distribution that caused
863 "tools\Makefile.nmake" not to be in the source code release. You can
864 download it with the URL
865 http://www.ethereal.com/cgi-bin/viewcvs.cgi/*checkout*/ethereal/tools/
866 Makefile.nmake?rev=1.5. Put it into "tools\Makefile.nmake" and try the
870 Q 5.1: When I use Ethereal to capture packets, I see only packets to
871 and from my machine, or I'm not seeing all the traffic I'm expecting
872 to see from or to the machine I'm trying to monitor.
874 A: This might be because the interface on which you're capturing is
875 plugged into a switch; on a switched network, unicast traffic between
876 two ports will not necessarily appear on other ports - only broadcast
877 and multicast traffic will be sent to all ports.
879 Note that even if your machine is plugged into a hub, the "hub" may be
880 a switched hub, in which case you're still on a switched network.
882 Note also that on the Linksys Web site, they say that their
883 auto-sensing hubs "broadcast the 10Mb packets to the port that operate
884 at 10Mb only and broadcast the 100Mb packets to the ports that operate
885 at 100Mb only", which would indicate that if you sniff on a 10Mb port,
886 you will not see traffic coming sent to a 100Mb port, and vice versa.
887 This problem has also been reported for Netgear dual-speed hubs, and
888 may exist for other "auto-sensing" or "dual-speed" hubs.
890 Some switches have the ability to replicate all traffic on all ports
891 to a single port so that you can plug your analyzer into that single
892 port to sniff all traffic. You would have to check the documentation
893 for the switch to see if this is possible and, if so, to see how to do
894 this. See, for example:
895 * this documentation from Cisco on the Switched Port Analyzer (SPAN)
896 feature on Catalyst switches;
897 * documentation from HP on how to set "monitoring"/"mirroring" on
898 ports on the console for HP Advancestack Switch 208 and 224;
899 * the "Network Monitoring Port Features" section of chapter 6 of
900 documentation from HP for HP ProCurve Switches 1600M, 2424M,
902 * the "Switch Port-Mirroring" section of chapter 6 of documentation
903 from Extreme Networks for their Summit 200 switches;
904 * the documentation on "Configuring Port Mirroring and Monitoring"
905 in Foundry Networks' documentation for their FastIron Edge
907 * the documentation on "Configuring Port Mirroring and Monitoring"
908 in Foundry Networks' documentation for their BigIron MG8 Layer 3
910 * the "Port Monitor" subsection of the "Status Monitor and
911 Statistics" section of the documentation from Foundry Networks for
912 their EdgeIron 4802F and 10GC2F switches;
913 * the "Configuring Port Mirroring" section of chapter 3 of the
914 documentation from Foundry Networks for their EdgeIron 24G,
915 2402CF, and 4802CF switches;
916 * the documentation on "Configuring Port Mirroring and Monitoring"
917 in Foundry Networks' documentation for their other switches and
920 Note also that many firewall/NAT boxes have a switch built into them;
921 this includes many of the "cable/DSL router" boxes. If you have a box
922 of that sort, that has a switch with some number of Ethernet ports
923 into which you plug machines on your network, and another Ethernet
924 port used to connect to a cable or DSL modem, you can, at least, sniff
925 traffic between the machines on your network and the Internet by
926 plugging the Ethernet port on the router going to the modem, the
927 Ethernet port on the modem, and the machine on which you're running
928 Ethereal into a hub (make sure it's not a switching hub, and that, if
929 it's a dual-speed hub, all three of those ports are running at the
932 If your machine is not plugged into a switched network or a dual-speed
933 hub, or it is plugged into a switched network but the port is set up
934 to have all traffic replicated to it, the problem might be that the
935 network interface on which you're capturing doesn't support
936 "promiscuous" mode, or because your OS can't put the interface into
937 promiscuous mode. Normally, network interfaces supply to the host
939 * packets sent to one of that host's link-layer addresses;
941 * multicast packets sent to a multicast address that the host has
942 configured the interface to accept.
944 Most network interfaces can also be put in "promiscuous" mode, in
945 which they supply to the host all network packets they see. Ethereal
946 will try to put the interface on which it's capturing into promiscuous
947 mode unless the "Capture packets in promiscuous mode" option is turned
948 off in the "Capture Options" dialog box, and Tethereal will try to put
949 the interface on which it's capturing into promiscuous mode unless the
950 -p option was specified. However, some network interfaces don't
951 support promiscuous mode, and some OSes might not allow interfaces to
952 be put into promiscuous mode.
954 If the interface is not running in promiscuous mode, it won't see any
955 traffic that isn't intended to be seen by your machine. It will see
956 broadcast packets, and multicast packets sent to a multicast MAC
957 address the interface is set up to receive.
959 You should ask the vendor of your network interface whether it
960 supports promiscuous mode. If it does, you should ask whoever supplied
961 the driver for the interface (the vendor, or the supplier of the OS
962 you're running on your machine) whether it supports promiscuous mode
963 with that network interface.
965 In the case of token ring interfaces, the drivers for some of them, on
966 Windows, may require you to enable promiscuous mode in order to
967 capture in promiscuous mode. Ask the vendor of the card how to do
968 this, or see, for example, this information on promiscuous mode on
969 some Madge token ring adapters (note that those cards can have
970 promiscuous mode disabled permanently, in which case you can't enable
973 In the case of wireless LAN interfaces, it appears that, when those
974 interfaces are promiscuously sniffing, they're running in a
975 significantly different mode from the mode that they run in when
976 they're just acting as network interfaces (to the extent that it would
977 be a significant effor for those drivers to support for promiscuously
978 sniffing and acting as regular network interfaces at the same time),
979 so it may be that Windows drivers for those interfaces don't support
982 Q 5.2: I can't see any TCP packets other than packets to and from my
983 machine, even though another analyzer on the network sees those
986 A: You're probably not seeing any packets other than unicast packets
987 to or from your machine, and broadcast and multicast packets; a switch
988 will normally send to a port only unicast traffic sent to the MAC
989 address for the interface on that port, and broadcast and multicast
990 traffic - it won't send to that port unicast traffic sent to a MAC
991 address for some other interface - and a network interface not in
992 promiscuous mode will receive only unicast traffic sent to the MAC
993 address for that interface, broadcast traffic, and multicast traffic
994 sent to a multicast MAC address the interface is set up to receive.
996 TCP doesn't use broadcast or multicast, so you will only see your own
997 TCP traffic, but UDP services may use broadcast or multicast so you'll
998 see some UDP traffic - however, this is not a problem with TCP
999 traffic, it's a problem with unicast traffic, as you also won't see
1000 all UDP traffic between other machines.
1002 I.e., this is probably the same question as this earlier one; see the
1003 response to that question.
1005 Q 5.3: I'm only seeing ARP packets when I try to capture traffic.
1007 A: You're probably on a switched network, and running Ethereal on a
1008 machine that's not sending traffic to the switch and not being sent
1009 any traffic from other machines on the switch. ARP packets are often
1010 broadcast packets, which are sent to all switch ports.
1012 I.e., this is probably the same question as this earlier one; see the
1013 response to that question.
1015 Q 5.4: I'm running Ethereal on Windows; why does some network
1016 interface on my machine not show up in the list of interfaces in the
1017 "Interface:" field in the dialog box popped up by "Capture->Start",
1018 and/or why does Ethereal give me an error if I try to capture on that
1021 A: If you are running Ethereal on Windows NT 4.0, Windows 2000,
1022 Windows XP, or Windows Server, and this is the first time you have run
1023 a WinPcap-based program (such as Ethereal, or Tethereal, or WinDump,
1024 or Analyzer, or...) since the machine was rebooted, you need to run
1025 that program from an account with administrator privileges; once you
1026 have run such a program, you will not need administrator privileges to
1027 run any such programs until you reboot.
1029 If you are running on Windows 95/98/Me, or if you are running on
1030 Windows NT 4.0/2000/XP/Server and have administrator privileges or a
1031 WinPcap-based program has been run with those privileges since the
1032 machine rebooted, then note that Ethereal relies on the WinPcap
1033 library, on the WinPcap device driver, and on the facilities that come
1034 with the OS on which it's running in order to do captures.
1036 Therefore, if the OS, the WinPcap library, or the WinPcap driver don't
1037 support capturing on a particular network interface device, Ethereal
1038 won't be able to capture on that device.
1041 1. 2.02 and earlier versions of the WinPcap driver and library that
1042 Ethereal uses for packet capture didn't support Token Ring
1043 interfaces; versions 2.1 and later support Token Ring, and the
1044 current version of Ethereal works with (and, in fact, requires)
1045 WinPcap 2.1 or later.
1046 If you are having problems capturing on Token Ring interfaces, and
1047 you have WinPcap 2.02 or an earlier version of WinPcap installed,
1048 you should uninstall WinPcap, download and install the current
1049 version of WinPcap, and then install the latest version of
1051 2. On Windows 95, 98, or Me, sometimes more than one interface will
1052 be given the same name; if that is the case, you will only be able
1053 to capture on one of those interfaces - it's not clear to which
1054 one the name, when used in a WinPcap-based application, will
1055 refer. For example, if you have a PPP serial interface and a VPN
1056 interface, they might show up with the same name, for example
1057 "ppp-mac", and if you try to capture on "ppp-mac", it might not
1058 capture on the interface you're currently using. In that case, you
1059 might, for example, have to remove the VPN interface from the
1060 system in order to capture on the PPP serial interface.
1061 3. WinPcap 3.0 doesn't support PPP WAN interfaces, and WinPcap 2.3
1062 doesn't support PPP WAN interfaces on Windows NT/2000/XP/Server,
1063 so Ethereal cannot capture packets on those devices with WinPcap
1064 3.0, or with WInPcap 2.x when running on Windows
1065 NT/2000/XP/Server. Regular dial-up lines, ISDN lines, and various
1066 other lines such as T1/E1 lines are all PPP interfaces. This may
1067 cause the interface not to show up on the list of interfaces in
1068 the "Capture Options" dialog.
1069 4. WinPcap prior to 3.0 does not support multiprocessor machines
1070 (note that machines with a single multi-threaded processor, such
1071 as Intel's new multi-threaded x86 processors, are multiprocessor
1072 machines as far as the OS and WinPcap are concerned), and recent
1073 2.x versions of WinPcap refuse to operate if they detect that
1074 they're running on a multiprocessor machine, which means that they
1075 may not show any network interfaces. You will need to use WinPcap
1076 3.0 to capture on a multiprocessor machine.
1078 If an interface doesn't show up in the list of interfaces in the
1079 "Interface:" field, and you know the name of the interface, try
1080 entering that name in the "Interface:" field and capturing on that
1083 If the attempt to capture on it succeeds, the interface is somehow not
1084 being reported by the mechanism Ethereal uses to get a list of
1085 interfaces; please report this to ethereal-dev@ethereal.com giving
1086 full details of the problem, including
1087 * the operating system you're using, and the version of that
1089 * the type of network device you're using.
1091 If you are having trouble capturing on a particular network interface,
1092 first try capturing on that device with WinDump; see the WinDump Web
1093 site or the local mirror of the WinDump Web site for information on
1096 If you can capture on the interface with WinDump, send mail to
1097 ethereal-users@ethereal.com giving full details of the problem,
1099 * the operating system you're using, and the version of that
1101 * the type of network device you're using;
1102 * the error message you get from Ethereal.
1104 If you cannot capture on the interface with WinDump, this is almost
1105 certainly a problem with one or more of:
1106 * the operating system you're using;
1107 * the device driver for the interface you're using;
1108 * the WinPcap library and/or the WinPcap device driver;
1110 so first check the WinPcap FAQ, the local mirror of that FAQ, or the
1111 Wiretapped.net mirror of that FAQ, to see if your problem is mentioned
1112 there. If not, then see the WinPcap support page (or the local mirror
1113 of that page) - check the "Submitting bugs" section.
1115 Q 5.5: I'm running Ethereal on Windows; why do no network interfaces
1116 show up in the list of interfaces in the "Interface:" field in the
1117 dialog box popped up by "Capture->Start"?
1119 A: This is really the same question as the previous one; see the
1120 response to that question.
1122 Q 5.6: I'm running Ethereal on Windows; why doesn't my serial
1123 port/ADSL modem/ISDN modem/show up in the list of interfaces in the
1124 "Interface:" field in the dialog box popped up by "Capture->Start"?
1126 A: All of those devices support Internet access using the
1127 Point-to-Point (PPP) protocol; WinPcap 3.0 doesn't support PPP
1128 interfaces, and WinPcap 2.x doesn't support PPP interfaces on Windows
1129 NT/2000/XP/Server, so Ethereal cannot capture packets on those devices
1130 with WinPcap 3.0, or with WinPcap 2.x when running on Windows
1131 NT/2000/XP/Server. This may cause the interface not to show up on the
1132 list of interfaces in the "Capture Options" dialog.
1134 Q 5.7: I'm running Ethereal on a UNIX-flavored OS; why does some
1135 network interface on my machine not show up in the list of interfaces
1136 in the "Interface:" field in the dialog box popped up by
1137 "Capture->Start", and/or why does Ethereal give me an error if I try
1138 to capture on that interface?
1140 A: You may need to run Ethereal from an account with sufficient
1141 privileges to capture packets, such as the super-user account. Only
1142 those interfaces that Ethereal can open for capturing show up in that
1143 list; if you don't have sufficient privileges to capture on any
1144 interfaces, no interfaces will show up in the list.
1146 If you are running Ethereal from an account with sufficient
1147 privileges, then note that Ethereal relies on the libpcap library, and
1148 on the facilities that come with the OS on which it's running in order
1151 Therefore, if the OS or the libpcap library don't support capturing on
1152 a particular network interface device, Ethereal won't be able to
1153 capture on that device.
1155 On Linux, note that you need to have "packet socket" support enabled
1156 in your kernel; see the "Packet socket" item in the Linux
1157 "Configure.help" file.
1159 On BSD, note that you need to have BPF support enabled in your kernel;
1160 see the documentation for your system for information on how to enable
1161 BPF support (if it's not enabled by default on your system).
1163 On DEC OSF/1, Digital UNIX, or Tru64 UNIX, note that you need to have
1164 packet filtering support in your kernel; the doconfig command will
1165 allow you to configure and build a new kernel with that option.
1167 On Solaris, note that libpcap 0.6.2 and earlier didn't support Token
1168 Ring interfaces; the current version, 0.7.2, does support Token Ring,
1169 and the current version of Ethereal works with libcap 0.7.2 and later.
1171 If an interface doesn't show up in the list of interfaces in the
1172 "Interface:" field, and you know the name of the interface, try
1173 entering that name in the "Interface:" field and capturing on that
1176 If the attempt to capture on it succeeds, the interface is somehow not
1177 being reported by the mechanism Ethereal uses to get a list of
1178 interfaces; please report this to ethereal-dev@ethereal.com giving
1179 full details of the problem, including
1180 * the operating system you're using, and the version of that
1181 operating system (for Linux, give both the version number of the
1182 kernel and the name and version number of the distribution you're
1184 * the type of network device you're using.
1186 If you are having trouble capturing on a particular network interface,
1187 and you've made sure that (on platforms that require it) you've
1188 arranged that packet capture support is present, as per the above,
1189 first try capturing on that device with tcpdump.
1191 If you can capture on the interface with tcpdump, send mail to
1192 ethereal-users@ethereal.com giving full details of the problem,
1194 * the operating system you're using, and the version of that
1195 operating system (for Linux, give both the version number of the
1196 kernel and the name and version number of the distribution you're
1198 * the type of network device you're using;
1199 * the error message you get from Ethereal.
1201 If you cannot capture on the interface with tcpdump, this is almost
1202 certainly a problem with one or more of:
1203 * the operating system you're using;
1204 * the device driver for the interface you're using;
1205 * the libpcap library;
1207 so you should report the problem to the company or organization that
1208 produces the OS (in the case of a Linux distribution, report the
1209 problem to whoever produces the distribution).
1211 You may also want to ask the ethereal-users@ethereal.com and the
1212 tcpdump-workers@tcpdump.org mailing lists to see if anybody happens to
1213 know about the problem and know a workaround or fix for the problem.
1214 In your mail, please give full details of the problem, as described
1215 above, and also indicate that the problem occurs with tcpdump not just
1218 Q 5.8: I'm running Ethereal on a UNIX-flavored OS; why do no network
1219 interfaces show up in the list of interfaces in the "Interface:" field
1220 in the dialog box popped up by "Capture->Start"?
1222 A: This is really the same question as the previous one; see the
1223 response to that question.
1225 Q 5.9: Can Ethereal capture on (my T1/E1 line, SS7 links, etc.)?
1227 A: Ethereal can only capture on devices supported by libpcap/WinPcap.
1228 On most OSes, only devices that can act as network interfaces of the
1229 type that support IP are supported as capture devices for
1230 libpcap/WinPcap, although the device doesn't necessarily have to be
1231 running as an IP interface in order to support traffic capture.
1233 On Linux and FreeBSD, libpcap 0.8 and later support the API for Endace
1234 Measurement Systems' DAG cards, so that a system with one of those
1235 cards, and its driver and libraries, installed can capture traffic
1236 with those cards with libpcap-based applications. You would either
1237 have to have a version of Ethereal built with that version of libpcap,
1238 or a dynamically-linked version of Ethereal and a shared libpcap
1239 library with DAG support, in order to do so with Ethereal. You should
1240 ask Endace whether that could be used to capture traffic on, for
1241 example, your T1/E1 link.
1242 There is currently no hardware to support capturing on SS7 links with
1243 libpcap. (Note that the fact that Ethereal includes dissectors for
1244 many SS7 protocols doesn't imply that it can capture traffic from SS7
1245 links; those protocols can be run over Internet protocols.)
1247 Q 5.10: How do I put an interface into promiscuous mode?
1249 A: By not disabling promiscuous mode when running Ethereal or
1252 Note, however, that:
1253 * the form of promiscuous mode that libpcap (the library that
1254 programs such as tcpdump, Ethereal, etc. use to do packet capture)
1255 turns on will not necessarily be shown if you run ifconfig on the
1256 interface on a UNIX system;
1257 * some network interfaces might not support promiscuous mode, and
1258 some drivers might not allow promiscuous mode to be turned on -
1259 see this earlier question for more information on that;
1260 * the fact that you're not seeing any traffic, or are only seeing
1261 broadcast traffic, or aren't seeing any non-broadcast traffic
1262 other than traffic to or from the machine running Ethereal, does
1263 not mean that promiscuous mode isn't on - see this earlier
1264 question for more information on that.
1266 I.e., this is probably the same question as this earlier one; see the
1267 response to that question.
1269 Q 5.11: I can set a display filter just fine, but capture filters
1272 A: Capture filters currently use a different syntax than display
1273 filters. Here's the corresponding section from the ethereal(1) man
1276 "Display filters in Ethereal are very powerful; more fields are
1277 filterable in Ethereal than in other protocol analyzers, and the
1278 syntax you can use to create your filters is richer. As Ethereal
1279 progresses, expect more and more protocol fields to be allowed in
1282 Packet capturing is performed with the pcap library. The capture
1283 filter syntax follows the rules of the pcap library. This syntax is
1284 different from the display filter syntax."
1286 The capture filter syntax used by libpcap can be found in the
1287 tcpdump(8) man page.
1289 Q 5.12: I'm entering valid capture filters, but I still get "parse
1292 A: There is a bug in some versions of libpcap/WinPcap that cause it to
1293 report parse errors even for valid expressions if a previous filter
1294 expression was invalid and got a parse error.
1296 Try exiting and restarting Ethereal; if you are using a version of
1297 libpcap/WinPcap with this bug, this will "erase" its memory of the
1298 previous parse error. If the capture filter that got the "parse error"
1299 now works, the earlier error with that filter was probably due to this
1302 The bug was fixed in libpcap 0.6; 0.4[.x] and 0.5[.x] versions of
1303 libpcap have this bug, but 0.6[.x] and later versions don't.
1305 Versions of WinPcap prior to 2.3 are based on pre-0.6 versions of
1306 libpcap, and have this bug; WinPcap 2.3 is based on libpcap 0.6.2, and
1307 doesn't have this bug.
1309 If you are running Ethereal on a UNIX-flavored platform, run "ethereal
1310 -v", or select "About Ethereal..." from the "Help" menu in Ethereal,
1311 to see what version of libpcap it's using. If it's not 0.6 or later,
1312 you will need either to upgrade your OS to get a later version of
1313 libpcap, or will need to build and install a later version of libpcap
1314 from the tcpdump.org Web site and then recompile Ethereal from source
1315 with that later version of libpcap.
1317 If you are running Ethereal on Windows with a pre-2.3 version of
1318 WinPcap, you will need to un-install WinPcap and then download and
1319 install WinPcap 2.3.
1321 Q 5.13: I saved a filter and tried to use its name to filter the
1322 display, but I got an "Unexpected end of filter string" error.
1324 A: You cannot use the name of a saved display filter as a filter. To
1325 filter the display, you can enter a display filter expression - not
1326 the name of a saved display filter - in the "Filter:" box at the
1327 bottom of the display, and type the key or press the "Apply" button
1328 (that does not require you to have a saved filter), or, if you want to
1329 use a saved filter, you can press the "Filter:" button, select the
1330 filter in the dialog box that pops up, and press the "OK" button.
1332 Q 5.14: Why am I seeing lots of packets with incorrect TCP checksums?
1334 A: If the packets that have incorrect TCP checksums are all being sent
1335 by the machine on which Ethereal is running, this is probably because
1336 the network interface on which you're capturing does TCP checksum
1337 offloading. That means that the TCP checksum is added to the packet by
1338 the network interface, not by the OS's TCP/IP stack; when capturing on
1339 an interface, packets being sent by the host on which you're capturing
1340 are directly handed to the capture interface by the OS, which means
1341 that they are handed to the capture interface without a TCP checksum
1342 being added to them.
1344 The only way to prevent this from happening would be to disable TCP
1345 checksum offloading, but
1346 1. that might not even be possible on some OSes;
1347 2. that could reduce networking performance significantly.
1349 However, you can disable the check that Ethereal does of the TCP
1350 checksum, so that it won't report any packets as having TCP checksum
1351 errors, and so that it won't refuse to do TCP reassembly due to a
1352 packet having an incorrect TCP checksum. That can be set as an
1353 Ethereal preference by selecting "Preferences" from the "Edit" menu,
1354 opening up the "Protocols" list in the left-hand pane of the
1355 "Preferences" dialog box, selecting "TCP", from that list, turning off
1356 the "Check the validity of the TCP checksum when possible" option,
1357 clicking "Save" if you want to save that setting in your preference
1358 file, and clicking "OK".
1360 It can also be set on the Ethereal or Tethereal command line with a -o
1361 tcp.check_checksum:false command-line flag, or manually set in your
1362 preferences file by adding a tcp.check_checksum:false line.
1364 Q 5.15: I've just installed Ethereal, and the traffic on my local LAN
1367 A: We have a collection of strange and exotic sample capture files at
1368 http://www.ethereal.com/sample/
1370 Q 5.16: When I run Ethereal on Solaris 8, it dies with a Bus Error
1373 A: Some versions of the GTK+ library from www.sunfreeware.org appear
1374 to be buggy, causing Ethereal to drop core with a Bus Error.
1375 Un-install those packages, and try getting the 1.2.10 version from
1376 that site, or the version from The Written Word, or the version from
1377 Sun's GNOME distribution, or the version from the supplemental
1378 software CD that comes with the Solaris media kit, or build it from
1379 source from the GTK Web site. Update the GLib library to the 1.2.10
1380 version, from the same source, as well. (If you get the 1.2.10
1381 versions from www.sunfreeware.org, and the problem persists,
1382 un-install them and try installing one of the other versions
1385 Similar problems may exist with older versions of GTK+ for earlier
1386 versions of Solaris.
1388 Q 5.17: When I run Tethereal with the "-x" option, it crashes with an
1389 error "** ERROR **: file print.c: line 691 (print_line): should not be
1392 A: This is a bug in Ethereal 0.10.0a, which is fixed in the Ethereal
1393 CVS tree and will thus be fixed in the next release. To work around
1394 the bug, don't use "-x" unless you're also using "-V"; note that "-V"
1395 produces a full dissection of each packet, so you might not want to
1398 To get a fixed version, either build the current CVS version from
1399 anonymous CVS or a nightly CVS snapshot, or apply to tethereal.c in
1400 the 0.10.0a source tarball the changes between the broken and the
1401 fixed versions, which you can download with the URL
1402 http://www.ethereal.com/cgi-bin/viewcvs.cgi/ethereal/tethereal.c.diff?
1403 r2=1.211&r1=1.210&diff_format=u and (re-)build from source. It might
1404 be easier to get the CVS version than to get the patch and apply it to
1405 the 0.10.0a source tarball, but it's probably easier to build from the
1406 source tarball than from the CVS version, as you'll need to have more
1407 tools and make more steps to generate from the CVS version some files
1408 that are bundled with the source tarball.
1410 Note that to build from the 0.10.0a source tarball on Windows with
1411 Microsoft Visual C++, you will need to get a file that was missing
1412 from the 0.10.0a source tarball; see the FAQ for that problem.
1414 Q 5.18: When I run Ethereal on Windows NT, it dies with a Dr. Watson
1415 error, reporting an "Integer division by zero" exception, when I start
1418 A: In at least some case, this appears to be due to using the default
1419 VGA driver; if that's not the correct driver for your video card, try
1420 running the correct driver for your video card.
1422 Q 5.19: When I try to run Ethereal, it complains about
1423 sprint_realloc_objid being undefined.
1425 A: Ethereal can only be linked with version 4.2.2 or later of UCD
1426 SNMP. Your version of Ethereal was dynamically linked with such a
1427 version of UCD SNMP; however, you have an older version of UCD SNMP
1428 installed, which means that when Ethereal is run, it tries to link to
1429 the older version, and fails. You will have to replace that version of
1430 UCD SNMP with version 4.2.2 or a later version.
1432 Q 5.20: I'm running Ethereal on Linux; why do my time stamps have only
1433 100ms resolution, rather than 1us resolution?
1435 A: Ethereal gets time stamps from libpcap/WinPcap, and libpcap/WinPcap
1436 get them from the OS kernel, so Ethereal - and any other program using
1437 libpcap, such as tcpdump - is at the mercy of the time stamping code
1438 in the OS for time stamps.
1440 At least on x86-based machines, Linux can get high-resolution time
1441 stamps on newer processors with the Time Stamp Counter (TSC) register;
1442 for example, Intel x86 processors, starting with the Pentium Pro, and
1443 including all x86 processors since then, have had a TSC, and other
1444 vendors probably added the TSC at some point to their families of x86
1447 The Linux kernel must be configured with the CONFIG_X86_TSC option
1448 enabled in order to use the TSC. Make sure this option is enabled in
1451 In addition, some Linux distributions may have bugs in their versions
1452 of the kernel that cause packets not to be given high-resolution time
1453 stamps even if the TSC is enabled. See, for example, bug 61111 for Red
1454 Hat Linux 7.2. If your distribution has a bug such as this, you may
1455 have to run a standard kernel from kernel.org in order to get
1456 high-resolution time stamps.
1458 Q 5.21: I'm capturing packets on {Windows 95, Windows 98, Windows Me};
1459 why are the time stamps on packets wrong?
1461 A: This is due to a bug in WinPcap. The bug should be fixed in WinPcap
1464 Q 5.22: When I try to run Ethereal on Windows, it fails to run because
1465 it can't find packet.dll.
1467 A: In older versions of Ethereal, there were two binary distributions
1468 available for Windows, one that supported capturing packets, and one
1469 that didn't. The version that supported capturing packets required
1470 that you install the WinPcap driver; if you didn't install it, it
1471 would fail to run because it couldn't find packet.dll.
1473 The current version of Ethereal has only one binary distribution for
1474 Windows; that version will check whether WinPcap is installed and, if
1475 it's not, will disable support for packet capture.
1477 The WinPcap driver and libraries can be downloaded from the WinPcap
1478 Web site, the local mirror of the WinPcap Web site, or the
1479 Wiretapped.net mirror of the WinPcap site.
1481 Q 5.23: I'm running Ethereal on Windows NT/2000/XP/Server; my machine
1482 has a PPP (dial-up POTS, ISDN, etc.) interface, and it shows up in the
1483 "Interface" item in the "Capture Options" dialog box. Why can no
1484 packets be sent on or received from that network while I'm trying to
1485 capture traffic on that interface?
1487 A: WinPcap doesn't support PPP WAN interfaces on Windows
1488 NT/2000/XP/Server; one symptom that may be seen is that attempts to
1489 capture in promiscuous mode on the interface cause the interface to be
1490 incapable of sending or receiving packets. You can disable promiscuous
1491 mode using the -p command-line flag or the item in the "Capture
1492 Preferences" dialog box, but this may mean that outgoing packets, or
1493 incoming packets, won't be seen in the capture.
1495 Q 5.24: I'm running Ethereal on Windows 95/98/Me, on a machine with
1496 more than one network adapter of the same type; Ethereal shows all of
1497 those adapters with the same name, but I can't use any of those
1498 adapters other than the first one.
1500 A: Unfortunately, Windows 95/98/Me gives the same name to multiple
1501 instances of the type of same network adapter. Therefore, WinPcap
1502 cannot distinguish between them, so a WinPcap-based application can
1503 capture only on the first such interface; Ethereal is a
1504 libpcap/WinPcap-based application.
1506 Q 5.25: I'm running Ethereal on Windows, and I'm not seeing any
1507 traffic being sent by the machine running Ethereal.
1509 A: If you are running some form of VPN client software, it might be
1510 causing this problem; people have seen this problem when they have
1511 Check Point's VPN software installed on their machine. If that's the
1512 cause of the problem, you will have to remove the VPN software in
1513 order to have Ethereal (or any other application using WinPcap) see
1514 outgoing packets; unfortunately, neither we nor the WinPcap developers
1515 know any way to make WinPcap and the VPN software work well together.
1517 Also, some drivers for Windows (especially some wireless network
1518 interface drivers) apparently do not, when running in promiscuous
1519 mode, arrange that outgoing packets are delivered to the software that
1520 requested that the interface run promiscuously; try turning
1521 promiscuous mode off.
1523 Q 5.26: I'm trying to capture traffic but I'm not seeing any.
1525 A: Is the machine running Ethereal sending out any traffic on the
1526 network interface on which you're capturing, or receiving any traffic
1527 on that network, or is there any broadcast traffic on the network or
1528 multicast traffic to a multicast group to which the machine running
1531 If not, this may just be a problem with promiscuous sniffing, either
1532 due to running on a switched network or a dual-speed hub, or due to
1533 problems with the interface not supporting promiscuous mode; see the
1534 response to this earlier question.
1536 Otherwise, on Windows, see the response to this question and, on a
1537 UNIX-flavored OS, see the response to this question.
1539 Q 5.27: I have an XXX network card on my machine; if I try to capture
1540 on it, my machine crashes or resets itself.
1542 A: This is almost certainly a problem with one or more of:
1543 * the operating system you're using;
1544 * the device driver for the interface you're using;
1545 * the libpcap/WinPcap library and, if this is Windows, the WinPcap
1549 * if you are using Windows, see the WinPcap support page (or the
1550 local mirror of that page) - check the "Submitting bugs" section;
1551 * if you are using some Linux distribution, some version of BSD, or
1552 some other UNIX-flavored OS, you should report the problem to the
1553 company or organization that produces the OS (in the case of a
1554 Linux distribution, report the problem to whoever produces the
1557 Q 5.28: My machine crashes or resets itself when I select "Start" from
1558 the "Capture" menu or select "Preferences" from the "Edit" menu.
1560 A: Both of those operations cause Ethereal to try to build a list of
1561 the interfaces that it can open; it does so by getting a list of
1562 interfaces and trying to open them. There is probably an OS, driver,
1563 or, for Windows, WinPcap bug that causes the system to crash when this
1564 happens; see the previous question.
1566 Q 5.29: Does Ethereal work on Windows Me?
1568 A: Yes, but if you want to capture packets, you will need to install
1569 the latest version of WinPcap, as 2.02 and earlier versions of WinPcap
1570 didn't support Windows Me. You should also install the latest version
1571 of Ethereal as well.
1573 Q 5.30: Does Ethereal work on Windows XP?
1575 A: Yes, but if you want to capture packets, you will need to install
1576 the latest version of WinPcap, as 2.2 and earlier versions of WinPcap
1577 didn't support Windows XP.
1579 Q 5.31: Why doesn't Ethereal correctly identify RTP packets? It shows
1582 A: Ethereal can identify a UDP datagram as containing a packet of a
1583 particular protocol running atop UDP only if
1584 1. The protocol in question has a particular standard port number,
1585 and the UDP source or destination port number is that port
1586 2. Packets of that protocol can be identified by looking for a
1587 "signature" of some type in the packet - i.e., some data that, if
1588 Ethereal finds it in some particular part of a packet, means that
1589 the packet is almost certainly a packet of that type.
1590 3. Some other traffic earlier in the capture indicated that, for
1591 example, UDP traffic between two particular addresses and ports
1592 will be RTP traffic.
1594 RTP doesn't have a standard port number, so 1) doesn't work; it
1595 doesn't, as far as I know, have any "signature", so 2) doesn't work.
1597 That leaves 3). If there's RTSP traffic that sets up an RTP session,
1598 then, at least in some cases, the RTSP dissector will set things up so
1599 that subsequent RTP traffic will be identified. Currently, that's the
1600 only place we do that; there may be other places.
1602 However, there will always be places where Ethereal is simply
1603 incapable of deducing that a given UDP flow is RTP; a mechanism would
1604 be needed to allow the user to specify that a given conversation
1605 should be treated as RTP. As of Ethereal 0.8.16, such a mechanism
1606 exists; if you select a UDP or TCP packet, the right mouse button menu
1607 will have a "Decode As..." menu item, which will pop up a dialog box
1608 letting you specify that the source port, the destination port, or
1609 both the source and destination ports of the packet should be
1610 dissected as some particular protocol.
1612 Q 5.32: Why doesn't Ethereal show Yahoo Messenger packets in captures
1613 that contain Yahoo Messenger traffic?
1615 A: Ethereal only recognizes as Yahoo Messenger traffic packets to or
1616 from TCP port 3050 that begin with "YPNS", "YHOO", or "YMSG". TCP
1617 segments that start with the middle of a Yahoo Messenger packet that
1618 takes more than one TCP segment will not be recognized as Yahoo
1619 Messenger packets (even if the TCP segment also contains the beginning
1620 of another Yahoo Messenger packet).
1622 Q 5.33: Why do I get the error
1624 Gdk-ERROR **: Palettized display (256-colour) mode not supported on
1628 when I try to run Ethereal on Windows?
1630 A: Ethereal is built using the GTK+ toolkit, which supports most
1631 UNIX-flavored OSes, and also supports Windows.
1633 Windows versions of Ethereal before 0.9.14 were built with an older
1634 version of that toolkit, which didn't support 256-color mode on
1635 Windows - it required HiColor (16-bit colors) or more.
1637 Windows versions of Ethereal 0.9.14 and later are built with a version
1638 of that toolkit that supports 256-color mode; upgrade to the current
1639 version of Ethereal if you want to run on a display in 256-color mode.
1641 Q 5.34: When I capture on Windows in promiscuous mode, I can see
1642 packets other than those sent to or from my machine; however, those
1643 packets show up with a "Short Frame" indication, unlike packets to or
1644 from my machine. What should I do to arrange that I see those packets
1647 A: In at least some cases, this appears to be the result of PGPnet
1648 running on the network interface on which you're capturing; turn it
1649 off on that interface.
1651 Q 5.35: I'm capturing packets on a machine on a VLAN; why don't the
1652 packets I'm capturing have VLAN tags?
1654 A: You might be capturing on what might be called a "VLAN interface" -
1655 the way a particular OS makes VLANs plug into the networking stack
1656 might, for example, be to have a network device object for the
1657 physical interface, which takes VLAN packets, strips off the VLAN
1658 header and constructs an Ethernet header, and passes that packet to an
1659 internal network device object for the VLAN, which then passes the
1660 packets onto various higher-level protocol implementations.
1662 In order to see the raw Ethernet packets, rather than "de-VLANized"
1663 packets, you would have to capture not on the virtual interface for
1664 the VLAN, but on the interface corresponding to the physical network
1665 device, if possible.
1667 Q 5.36: How can I capture raw 802.11 packets, including non-data
1668 (management, beacon) packets?
1670 A: That would require that your 802.11 interface run in the mode
1671 called "monitor mode" or "RFMON mode". Not all operating systems
1672 support that and, even on operating systems that do support it, not
1673 all drivers, and thus not all cards, support it.
1675 NOTE: an interface running in monitor mode will, on most if not all
1676 platforms, not be able to act as a regular network interface; putting
1677 it into monitor mode will, in effect, take your machine off of
1678 whatever network it's on as long as the interface is in monitor mode,
1679 allowing it only to passively capture packets.
1681 This means that you should disable name resolution when capturing in
1682 monitor mode; otherwise, when Ethereal (or Tethereal, or tcpdump)
1683 tries to display IP addresses as host names, it will probably block
1684 for a long time trying to resolve the name because it will not be able
1685 to communicate with any DNS or NIS servers.
1687 Cisco Aironet cards:
1689 The only platforms that allow Ethereal to capture raw 802.11 packets
1690 on Cisco Aironet cards are:
1691 * Linux, with a 2.4.6 or later kernel;
1692 * FreeBSD 4.6 or later, as the driver in FreeBSD 4.5 has bugs that
1693 cause packets not to be captured correctly, and the driver in
1694 releases prior to 4.5 didn't support capturing raw packets.
1696 On FreeBSD, the ancontrol utility must be used. The command
1698 ancontrol -i anN -M flag
1700 is used to enable or disable monitor mode. If flag is 0, monitor mode
1701 will be turned off; otherwise, flag should be the sum of:
1702 * 1, to turn monitor mode on;
1703 * 2, if you want to capture traffic from any BSS rather than just
1704 the BSS with which the card is associated;
1705 * 4, if you want to see beacon packets (capturing beacon packets
1706 increases the CPU requirements of capturing).
1708 Don't add 8 in; Ethereal currently doesn't support the full Aironet
1711 On Linux with the driver in the 2.4.6 through 2.4.19 kernel, you will
1714 echo "Mode: rfmon" >/proc/driver/aironet/ethN/Config
1716 if your Aironet card is ethN. To capture traffic from any BSS rather
1717 than just the BSS with which the card is associated, do
1719 echo "Mode: y" >/proc/driver/aironet/ethN/Config
1721 and to return to the normal mode, do
1723 echo "Mode: ess" >/proc/driver/aironet/ethN/Config
1725 On Linux with the driver in the 2.4.20 or later kernel, or with the
1726 CVS drivers from the airo-linux SourceForge site, you will have to
1727 capture on the wifiN interface if your Aironet card is ethN, after
1728 running the commands listed above.
1730 In all of those cases, Ethereal would have to be linked with libpcap
1731 0.7.1 or later; this means that most Ethereal binary packages won't
1732 work unless they're statically linked with libpcap 0.7.1 or later, or
1733 they're dynamically linked with libpcap and your system has a libpcap
1734 0.7.1 or later shared library installed (note that libpcap source
1735 package from tcpdump.org does not build shared libraries). Some binary
1736 packaging mechanisms might make it difficult to install Ethereal
1737 binary packages built to depend on older libpcap binary packages if
1738 you have a newer libpcap binary package installed; the installer
1739 programs for those packaging mechanisms might support disabling
1740 dependency checking so that they will install Ethereal even though a
1741 newer version of libpcap is installed.
1743 Cards using the Prism II chip set (see this page of Linux 802.11
1744 information for details on wireless cards, including information on
1745 the chips they use):
1747 You can capture raw 802.11 packets with Prism II cards on Linux
1748 systems with the 0.1.14-pre6 or later version of the linux-wlan-ng
1749 drivers (see the linux-wlan page, and the linux-wlan-ng tarball
1752 Those require either Solomon Peachy's patch to libpcap 0.7.1 (see his
1753 libpcap-0.7.1-prism.diff file, or his RPMs of that version of
1754 libpcap), or the current CVS version of libpcap, which includes his
1755 patch (download it from the "Current Tar files" section of the
1756 tcpdump.org Web site). If you apply his patches to libpcap 0.7.1 and
1757 rebuild and install libpcap, or if you build and install the current
1758 CVS version of libpcap, you would have to rebuild Ethereal from
1759 source, linking it with that new version of libpcap; an Ethereal
1760 binary package would not work. Ethereal binary packages might work if
1761 you install the libpcap-0.7.1-1prism.i386.rpm RPM, as it might install
1762 a libpcap shared library in place of the one on your system.
1764 You may have to run a command to put the interface into monitor mode,
1765 or to change other interface settings, and you might have to capture
1766 on a wlanN interface rather than a ethN interface, in order to capture
1767 raw 802.11 packets. The interface settings are available in your
1768 wlan-ng.conf file. See the wlan-ng FAQ for additional information.
1770 On other platforms, capturing raw 802.11 packets on Prism II cards is
1771 not currently supported.
1773 Orinoco Silver and Gold cards:
1775 On Linux systems, there are patches on the Orinoco Monitor Mode Patch
1776 Page that should allow you to do capture raw 802.11 packets. You will
1777 have to determine which version of the driver you have, and select the
1780 Note that the page indicates that not all versions of the Orinoco
1781 firmware support this patch. It says, for some versions of the patch,
1782 "This patch should allow monitor mode with v8.10 firmware (untested w/
1783 8.42);" if you have version 8.10 or later firmware on your Orinoco
1784 cards, you might have to use those patches, with the corresponding
1785 versions of the Orinoco driver, in order to run in monitor mode.
1787 That patch is written for the drivers included with the pcmcia-cs
1788 drivers, but works equally well for the Orinoco drivers provided with
1789 Linux kernels up to 2.4.20. To apply a patch to your kernel drivers,
1790 simply copy the orinoco-09b-patch.diff file to the
1791 /usr/src/linux/drivers/net directory and patch according to the
1792 directions on the Orinoco Monitor Mode Patch Page. You can double-
1793 check the version of the Orinoco drivers that shipped with your kernel
1794 by examining the first few lines of the orinoco.c file.
1796 The Orinoco patches require either Solomon Peachy's patch to libpcap
1797 0.7.1 (see his libpcap-0.7.1-prism.diff file, or his RPMs of that
1798 version of libpcap), or the current CVS version of libpcap, which
1799 includes his patch (download it from the "Current Tar files" section
1800 of the tcpdump.org Web site). If you apply his patches to libpcap
1801 0.7.1 and rebuild and install libpcap, or if you build and install the
1802 current CVS version of libpcap, you would have to rebuild Ethereal
1803 from source, linking it with that new version of libpcap; an Ethereal
1804 binary package would not work. Ethereal binary packages might work if
1805 you install the libpcap-0.7.1-1prism.i386.rpm RPM, as it might install
1806 a libpcap shared library in place of the one on your system.
1808 On other platforms, capturing raw 802.11 packets on Orinoco cards is
1809 not currently supported.
1811 Cards with the Atheros Communications AR5000 or AR5001 chipsets:
1813 You can capture raw 802.11 packets with AR5K cards on Linux systems
1814 with the v5_ar5k drivers. You will need the Linux wireless-tools
1815 version 25 or higher to put the card into monitor mode.
1817 Cards with the Texas Instruments ACX100 chipset:
1819 You can capture raw 802.11 packets with ACX100 cards on Linux systems
1820 with the ACX100 OSS drivers available from the ACX100 wireless network
1821 driver project SourceForge site.
1823 Other 802.11 interfaces:
1825 With other 802.11 interfaces, no platform allows Ethereal to capture
1826 raw 802.11 packets, as far as we know. If you know of other 802.11
1827 interfaces that are supported (note that there are many "Prism II
1828 cards", so your card might be a Prism II card), please let us know,
1829 and include URLs for sites containing any necessary patches to add
1832 On platforms that don't allow Ethereal to capture raw 802.11 packets,
1833 the 802.11 network will appear like an Ethernet to Ethereal.
1835 Q 5.37: I'm trying to capture 802.11 traffic on Windows; why am I not
1838 A: At least some 802.11 card drivers on Windows appear not to see any
1839 packets if they're running in promiscuous mode. Try turning
1840 promiscuous mode off; you'll only be able to see packets sent by and
1841 received by your machine, not third-party traffic, and it'll look like
1842 Ethernet traffic and won't include any management or control frames,
1843 but that's a limitation of the card drivers.
1845 Q 5.38: I'm trying to capture 802.11 traffic on Windows; why am I
1846 seeing packets received by the machine on which I'm capturing traffic,
1847 but not packets sent by that machine?
1849 A: This appears to be another problem with promiscuous mode; try
1852 Q 5.39: How can I capture packets with CRC errors?
1854 A: Ethereal can capture only the packets that the packet capture
1855 library - libpcap on UNIX-flavored OSes, and the WinPcap port to
1856 Windows of libpcap on Windows - can capture, and libpcap/WinPcap can
1857 capture only the packets that the OS's raw packet capture mechanism
1858 (or the WinPcap driver, and the underlying OS networking code and
1859 network interface drivers, on Windows) will allow it to capture.
1861 Unless the OS always supplies packets with errors such as invalid CRCs
1862 to the raw packet capture mechanism, or can be configured to do so,
1863 invalid CRCs to the raw packet capture mechanism, Ethereal - and other
1864 programs that capture raw packets, such as tcpdump - cannot capture
1865 those packets. You will have to determine whether your OS needs to be
1866 so configured and, if so, can be so configured, configure it if
1867 necessary and possible, and make whatever changes to libpcap and the
1868 packet capture program you're using are necessary, if any, to support
1869 capturing those packets.
1871 Most OSes probably do not support capturing packets with invalid CRCs
1872 on Ethernet, and probably do not support it on most other link-layer
1873 types. Some drivers on some OSes do support it, such as some Ethernet
1874 drivers on FreeBSD; in those OSes, you might always get those packets,
1875 or you might only get them if you capture in promiscuous mode (you'd
1876 have to determine which is the case).
1878 Note that libpcap does not currently supply to programs that use it an
1879 indication of whether the packet's CRC was invalid (because the
1880 drivers themselves do not supply that information to the raw packet
1881 capture mechanism); therefore, Ethereal will not indicate which
1882 packets had CRC errors unless the FCS was captured (see the next
1883 question) and you're using Ethereal 0.9.15 and later, in which case
1884 Ethereal will check the CRC and indicate whether it's correct or not.
1886 Q 5.40: How can I capture entire frames, including the FCS?
1888 A: Ethereal can't capture any data that the packet capture library -
1889 libpcap on UNIX-flavored OSes, and the WinPcap port to Windows of
1890 libpcap on Windows - can capture, and libpcap/WinPcap can capture only
1891 the data that the OS's raw packet capture mechanism (or the WinPcap
1892 driver, and the underlying OS networking code and network interface
1893 drivers, on Windows) will allow it to capture.
1895 For any particular link-layer network type, unless the OS supplies the
1896 FCS of a frame as part of the frame, or can be configured to do so,
1897 Ethereal - and other programs that capture raw packets, such as
1898 tcpdump - cannot capture the FCS of a frame. You will have to
1899 determine whether your OS needs to be so configured and, if so, can be
1900 so configured, configure it if necessary and possible, and make
1901 whatever changes to libpcap and the packet capture program you're
1902 using are necessary, if any, to support capturing the FCS of a frame.
1904 Most OSes do not support capturing the FCS of a frame on Ethernet, and
1905 probably do not support it on most other link-layer types. Some
1906 drivres on some OSes do support it, such as some (all?) Ethernet
1907 drivers on NetBSD and possibly the driver for Apple's gigabit Ethernet
1908 interface in Mac OS X; in those OSes, you might always get the FCS, or
1909 you might only get the FCS if you capture in promiscuous mode (you'd
1910 have to determine which is the case).
1912 Versions of Ethereal prior to 0.9.15 will not treat an Ethernet FCS in
1913 a captured packet as an FCS. 0.9.15 and later will attempt to
1914 determine whether there's an FCS at the end of the frame and, if it
1915 thinks there is, will display it as such, and will check whether it's
1916 the correct CRC-32 value or not.
1918 Q 5.41: Ethereal hangs after I stop a capture.
1920 A: The most likely reason for this is that Ethereal is trying to look
1921 up an IP address in the capture to convert it to a name (so that, for
1922 example, it can display the name in the source address or destination
1923 address columns), and that lookup process is taking a very long time.
1925 Ethereal calls a routine in the OS of the machine on which it's
1926 running to convert of IP addresses to the corresponding names. That
1927 routine probably does one or more of:
1928 * a search of a system file listing IP addresses and names;
1929 * a lookup using DNS;
1930 * on UNIX systems, a lookup using NIS;
1931 * on Windows systems, a NetBIOS-over-TCP query.
1933 If a DNS server that's used in an address lookup is not responding,
1934 the lookup will fail, but will only fail after a timeout while the
1935 system routine waits for a reply.
1937 In addition, on Windows systems, if the DNS lookup of the address
1938 fails, either because the server isn't responding or because there are
1939 no records in the DNS that could be used to map the address to a name,
1940 a NetBIOS-over-TCP query will be made. That query involves sending a
1941 message to the NetBIOS-over-TCP name service on that machine, asking
1942 for the name and other information about the machine. If the machine
1943 isn't running software that responds to those queries - for example,
1944 many non-Windows machines wouldn't be running that software - the
1945 lookup will only fail after a timeout. Those timeouts can cause the
1946 lookup to take a long time.
1948 If you disable network address-to-name translation - for example, by
1949 turning off the "Enable network name resolution" option in the "Name
1950 resolution" options in the dialog box you get by selecting
1951 "Preferences" from the "Edit" menu - the lookups of the address won't
1952 be done, which may speed up the process of reading the capture file
1953 after the capture is stopped. You can make that setting the default by
1954 using the "Save" button in that dialog box; note that this will save
1955 all your current preference settings.
1957 If Ethereal hangs when reading a capture even with network name
1958 resolution turned off, there might, for example, be a bug in one of
1959 Ethereal's dissectors for a protocol causing it to loop infinitely.
1960 The bug should be reported to the Ethereal developers' mailing list at
1961 ethereal-dev@ethereal.com.
1963 On UNIX-flavored OSes, please try to force Ethereal to dump core, by
1964 sending it a SIGABRT signal (usually signal 6) with the kill command,
1965 and then get a stack trace if you have a debugger installed. A stack
1966 trace can be obtained by using your debugger (gdb in this example),
1967 the Ethereal binary, and the resulting core file. Here's an example of
1968 how to use the gdb command backtrace to do so.
1971 ..... prints the stack trace
1975 The core dump file may be named "ethereal.core" rather than "core" on
1976 some platforms (e.g., BSD systems)
1978 Also, if at all possible, please send a copy of the capture file that
1979 caused the problem; when capturing packets, Ethereal normally writes
1980 captured packets to a temporary file, which will probably be in /tmp
1981 or /var/tmp on UNIX-flavored OSes and \TEMP on Windows, so the capture
1982 file will probably be there. It will have a name beginning with ether,
1983 with some mixture of letters and numbers after that. Please don't send
1984 a trace file greater than 1 MB when compressed. If the trace file
1985 contains sensitive information (e.g., passwords), then please do not
1988 Q 5.42: How can I search for, or filter, packets that have a
1989 particular string anywhere in them?
1991 A: If you want to do this when capturing, you can't. That's a feature
1992 that would be hard to implement in capture filters without changes to
1993 the capture filter code, which, on many platforms, is in the OS kernel
1994 and, on other platforms, is in the libpcap library.
1996 In releases prior to 0.9.14, you also can't search for, or filter,
1997 packets containing a particular string even after you've captured
2000 In 0.9.14, you can search for, but not filter, packets that have a
2001 particular string; this has been added to the "Find Frame" dialog
2002 ("Find Frame" under the "Edit" menu, or control-F).
2004 In 0.9.15 and later, you can search for those packets using either the
2005 mechanism introduced in 0.9.14 or using the new "contains" operator in
2006 filter expressions, which lets you search the entire packet or text
2007 string or byte string fields in the packet; the "contains" operator
2008 can also be used in expressions used to filter the display.
2011 Support can be found on the ethereal-users[AT]ethereal.com mailing
2013 For corrections/additions/suggestions for this page, please send email
2014 to: ethereal-web[AT]ethereal.com
2015 Last modified: Tue, January 27 2004.
git.samba.org / obnox / wireshark / wip.git / blob