1 <samba:parameter name="socket options"
6 xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
10 <para>Modern server operating systems are tuned for high
11 network performance in the majority of situations; when you set socket
12 options you are overriding those settings. Linux in particular has an
13 auto-tuning mechanism for buffer sizes that will be disabled if you
14 specify a socket buffer size. This can potentially cripple your
17 <para> Getting the socket options correct can make a big difference to
18 your performance, but getting them wrong can degrade it by just as
19 much. As with any other low level setting, if you must make changes
20 to it, make small changes and <emphasis>test</emphasis> the effect
21 before making any large changes.</para>
25 <para>This option allows you to set socket options
26 to be used when talking with the client.</para>
28 <para>Socket options are controls on the networking layer
29 of the operating systems which allow the connection to be
32 <para>This option will typically be used to tune your Samba server
33 for optimal performance for your local network. There is no way
34 that Samba can know what the optimal parameters are for your net,
35 so you must experiment and choose them yourself. We strongly
36 suggest you read the appropriate documentation for your operating
37 system first (perhaps <command moreinfo="none">man
38 setsockopt</command> will help).</para>
40 <para>You may find that on some systems Samba will say
41 "Unknown socket option" when you supply an option. This means you
42 either incorrectly typed it or you need to add an include file
43 to includes.h for your OS. If the latter is the case please
44 send the patch to <ulink url="mailto:samba-technical@lists.samba.org">
45 samba-technical@lists.samba.org</ulink>.</para>
47 <para>Any of the supported socket options may be combined
48 in any way you like, as long as your OS allows it.</para>
50 <para>This is the list of socket options currently settable
51 using this option:</para>
54 <listitem><para>SO_KEEPALIVE</para></listitem>
55 <listitem><para>SO_REUSEADDR</para></listitem>
56 <listitem><para>SO_BROADCAST</para></listitem>
57 <listitem><para>TCP_NODELAY</para></listitem>
58 <listitem><para>IPTOS_LOWDELAY</para></listitem>
59 <listitem><para>IPTOS_THROUGHPUT</para></listitem>
60 <listitem><para>SO_SNDBUF *</para></listitem>
61 <listitem><para>SO_RCVBUF *</para></listitem>
62 <listitem><para>SO_SNDLOWAT *</para></listitem>
63 <listitem><para>SO_RCVLOWAT *</para></listitem>
66 <para>Those marked with a <emphasis>'*'</emphasis> take an integer
67 argument. The others can optionally take a 1 or 0 argument to enable
68 or disable the option, by default they will be enabled if you
69 don't specify 1 or 0.</para>
71 <para>To specify an argument use the syntax SOME_OPTION = VALUE
72 for example <command moreinfo="none">SO_SNDBUF = 8192</command>. Note that you must
73 not have any spaces before or after the = sign.</para>
75 <para>If you are on a local network then a sensible option
78 <para><command moreinfo="none">socket options = IPTOS_LOWDELAY</command></para>
80 <para>If you have a local network then you could try:</para>
82 <para><command moreinfo="none">socket options = IPTOS_LOWDELAY TCP_NODELAY</command></para>
84 <para>If you are on a wide area network then perhaps try
85 setting IPTOS_THROUGHPUT. </para>
87 <para>Note that several of the options may cause your Samba
88 server to fail completely. Use these options with caution!</para>
91 <value type="default">TCP_NODELAY</value>
92 <value type="example">IPTOS_LOWDELAY</value>