1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 554440af675c..989f5538b8dd 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -164,6 +164,14 @@ tcp_congestion_control - STRING
         additional choices may be available based on kernel configuration.
         Default is set as part of kernel configuration.
 
+tcp_cookie_size - INTEGER
+        Default size of TCP Cookie Transactions (TCPCT) option, that may be
+        overridden on a per socket basis by the TCPCT socket option.
+        Values greater than the maximum (16) are interpreted as the maximum.
+        Values greater than zero and less than the minimum (8) are interpreted
+        as the minimum.  Odd values are interpreted as the next even value.
+        Default: 0 (off).
+
 tcp_dsack - BOOLEAN
         Allows TCP to send "duplicate" SACKs.