From 22bdd6966f2c3ccded984a37ba0b97470bcf9323 Mon Sep 17 00:00:00 2001 From: Tim Small Date: Fri, 16 Oct 2009 20:00:04 +0100 Subject: doc: update TCPMSS manpage with Linux 2.6.25 changes References: http://bugs.debian.org/551272 [j.eng: modified --set-mss option description to be understandable] Signed-off-by: Jan Engelhardt --- extensions/libxt_TCPMSS.man | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/extensions/libxt_TCPMSS.man b/extensions/libxt_TCPMSS.man index dbab918d..b5cb455f 100644 --- a/extensions/libxt_TCPMSS.man +++ b/extensions/libxt_TCPMSS.man @@ -34,9 +34,17 @@ configuration like: \-j TCPMSS \-\-clamp\-mss\-to\-pmtu .TP \fB\-\-set\-mss\fP \fIvalue\fP -Explicitly set MSS option to specified value. +Explicitly sets MSS option to specified value. If the MSS of the packet is +already lower than \fIvalue\fP, it will \fBnot\fP be increased (from Linux +2.6.25 onwards) to avoid more problems with hosts relying on a proper MSS. .TP \fB\-\-clamp\-mss\-to\-pmtu\fP Automatically clamp MSS value to (path_MTU \- 40 for IPv4; \-60 for IPv6). +This may not function as desired where asymmetric routes with differing +path MTU exist \(em the kernel uses the path MTU which it would use to send +packets from itself to the source and destination IP addresses. Prior to +Linux 2.6.25, only the path MTU to the destination IP address was +considered by this option; subsequent kernels also consider the path MTU +to the source IP address. .PP These options are mutually exclusive. -- cgit v1.2.3