From 84b183e9f7c116907e12b49cb9b99d837a3285ce Mon Sep 17 00:00:00 2001 From: lepton Date: Mon, 23 Apr 2012 21:17:09 +1200 Subject: [PATCH] tcp.7: Correct description for TCP_MAXSEG on modern kernel In tcp.7, about TCP_MAXSEG, it reads If this option is set before connection establishment, it also changes the MSS value announced to the other end in the initial packet. It is correct for kernel version 2.2, but it is not correct for modern kernel such as 2.4 and 2.6. On a linux box with a modern kernel, the setting for TCP_MAXSEG won't change the MSS value announced to the other end. Signed-off-by: Michael Kerrisk --- man7/tcp.7 | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/man7/tcp.7 b/man7/tcp.7 index 35db67169..afc160ca2 100644 --- a/man7/tcp.7 +++ b/man7/tcp.7 @@ -13,7 +13,7 @@ .\" be more or less up to date and complete as at Linux 2.6.27 .\" (other than the remaining FIXMEs in the page source below). .\" -.TH TCP 7 2012-03-20 "Linux" "Linux Programmer's Manual" +.TH TCP 7 2012-04-23 "Linux" "Linux Programmer's Manual" .SH NAME tcp \- TCP protocol .SH SYNOPSIS @@ -888,7 +888,8 @@ This option should not be used in code intended to be portable. .B TCP_MAXSEG .\" Present in Linux 1.0 The maximum segment size for outgoing TCP packets. -If this option is set before connection establishment, it also +In Linux 2.2 and earlier, +if this option is set before connection establishment, it also changes the MSS value announced to the other end in the initial packet. Values greater than the (eventual) interface MTU have no effect. TCP will also impose