diff options
| author | Arnaud Ebalard <arno@natisbad.org> | 2007-01-16 14:19:20 +0000 |
|---|---|---|
| committer | Patrick McHardy <kaber@trash.net> | 2007-01-16 14:19:20 +0000 |
| commit | e4076172c33810472d9d658554588b6e379a4fbe (patch) | |
| tree | 971ebca828b5dea3231025c39fe5ebd9862b0a79 /extensions/libip6t_TCPMSS.man | |
| parent | 9561606bd938ed4b2614716a08a2856d4ef5e995 (diff) | |
Add ip6tables TCPMSS extension (Arnaud Ebalard <arno@natisbad.org>)
Kernel part will go in 2.6.21.
Diffstat (limited to 'extensions/libip6t_TCPMSS.man')
| -rw-r--r-- | extensions/libip6t_TCPMSS.man | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/extensions/libip6t_TCPMSS.man b/extensions/libip6t_TCPMSS.man new file mode 100644 index 00000000..b4c357e8 --- /dev/null +++ b/extensions/libip6t_TCPMSS.man @@ -0,0 +1,42 @@ +This target allows to alter the MSS value of TCP SYN packets, to control +the maximum size for that connection (usually limiting it to your +outgoing interface's MTU minus 60). Of course, it can only be used +in conjunction with +.BR "-p tcp" . +It is only valid in the +.BR mangle +table. +.br +This target is used to overcome criminally braindead ISPs or servers +which block ICMPv6 Packet Too Big packets or are unable to send them. +The symptoms of this problem are that everything works fine from your +Linux firewall/router, but machines behind it can never exchange large +packets: +.PD 0 +.RS 0.1i +.TP 0.3i +1) +Web browsers connect, then hang with no data received. +.TP +2) +Small mail works fine, but large emails hang. +.TP +3) +ssh works fine, but scp hangs after initial handshaking. +.RE +.PD +Workaround: activate this option and add a rule to your firewall +configuration like: +.nf + ip6tables -t mangle -A FORWARD -p tcp --tcp-flags SYN,RST SYN \\ + -j TCPMSS --clamp-mss-to-pmtu +.fi +.TP +.BI "--set-mss " "value" +Explicitly set MSS option to specified value. +.TP +.B "--clamp-mss-to-pmtu" +Automatically clamp MSS value to (path_MTU - 60). +.TP +These options are mutually exclusive. + |