In my kernel log I found:lo: 5 rebuilds is over limit, route caching disabledI know what triggers route cache rebuilds (too long hash bucket chains), but what exactly gets disabled? Which device? How can I check if it is still disabled? How can I re-enable it?After this strange message I started having problems with other network devices like this:unregister_netdevice: waiting for TUNNEL_03 to become free. Usage count = 2 And routing cache seems to be guilty here
Re-enable route cache
networking;routing
After looking into kernel sources I worked it out.You have to increase your net.ipv4.rt_cache_rebuild_count and it works again.