From be1c5b53227ba8280f1ebb01c6f5da3c9eebdaad Mon Sep 17 00:00:00 2001 From: xu xin Date: Thu, 30 Dec 2021 03:28:56 +0000 Subject: Documentation: fix outdated interpretation of ip_no_pmtu_disc The updating way of pmtu has changed, but documentation is still in the old way. So this patch updates the interpretation of ip_no_pmtu_disc and min_pmtu. See commit 28d35bcdd3925 ("net: ipv4: don't let PMTU updates increase route MTU") Reported-by: Zeal Robot Signed-off-by: xu xin Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.rst | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index c04431144f7a..2572eecc3e86 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -25,7 +25,8 @@ ip_default_ttl - INTEGER ip_no_pmtu_disc - INTEGER Disable Path MTU Discovery. If enabled in mode 1 and a fragmentation-required ICMP is received, the PMTU to this - destination will be set to min_pmtu (see below). You will need + destination will be set to the smallest of the old MTU to + this destination and min_pmtu (see below). You will need to raise min_pmtu to the smallest interface MTU on your system manually if you want to avoid locally generated fragments. @@ -49,7 +50,8 @@ ip_no_pmtu_disc - INTEGER Default: FALSE min_pmtu - INTEGER - default 552 - minimum discovered Path MTU + default 552 - minimum Path MTU. Unless this is changed mannually, + each cached pmtu will never be lower than this setting. ip_forward_use_pmtu - BOOLEAN By default we don't trust protocol path MTUs while forwarding -- cgit