ipv4: improve documentation of ip_no_pmtu_disc

Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 2 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 3c12d9a7ed00..8a984e994e61 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -16,8 +16,12 @@ ip_default_ttl - INTEGER
         Default: 64 (as recommended by RFC1700)
 
 ip_no_pmtu_disc - BOOLEAN
-        Disable Path MTU Discovery.
-        default FALSE
+        Disable Path MTU Discovery. If enabled and a
+        fragmentation-required ICMP is received, the PMTU to this
+        destination will be set to 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.
+        Default: FALSE
 
 min_pmtu - INTEGER
         default 552 - minimum discovered Path MTU