diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index fbe427a6580cc5996a3352c4115327db371eaecc..5dcc06721bba158f3cbe95b0105668104eedec7b 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -738,8 +738,8 @@ rp_filter - INTEGER
 	to prevent IP spoofing from DDos attacks. If using asymmetric routing
 	or other complicated routing, then loose mode is recommended.
 
-	conf/all/rp_filter must also be set to non-zero to do source validation
-	on the interface
+	The max value from conf/{all,interface}/rp_filter is used
+	when doing source validation on the {interface}.
 
 	Default value is 0. Note that some distributions enable it
 	in startup scripts.