man: ip-route.8: Add notes about dropped IPv4 route cache

Signed-off-by: Phil Sutter <phil@nwl.cc>

diff --git a/man/man8/ip-route.8.in b/man/man8/ip-route.8.in
index d4fae3cc783ba4f38a11862b24ba19ebea8300c0..c0acaa0020ef786a5a67c2380aff77e26791a004 100644 (file)
--- a/man/man8/ip-route.8.in
+++ b/man/man8/ip-route.8.in
@@ -924,6 +924,12 @@ routes are left unchanged. Any routes specified in the data stream that
 already exist in the table will be ignored.
 .RE
 
+.SH NOTES
+Starting with Linux kernel version 3.6, there is no routing cache for IPv4
+anymore. Hence
+.B "ip route show cached"
+will never print any entries on systems with this or newer kernel versions.
+
 .SH EXAMPLES
 .PP
 ip ro