[IPV4]: Let people know where to obtain the ss tool from.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/Kconfig

@@ -355,7 +355,10 @@ config IP_TCPDIAG
 	default y
 	---help---
 	  Support for TCP socket monitoring interface used by native Linux
-	  tools such as ss.
+	  tools such as ss. ss is included in iproute2, currently downloadable
+	  at <http://developer.osdl.org/dev/iproute2>. If you want IPv6 support
+	  and have selected IPv6 as a module, you need to build this as a
+	  module too.
 	  
 	  If unsure, say Y.