On Fri, 22 Jun 2012, Rudy Zijlstra wrote:
let system run with IPv4& IPv6 routing for about 1 month
IPv6 routing will start to fail
IPv4 routing becomes slow and unpredictable
no obvious causes visible in the system. top and friends do not show a cpu hog
a reboot will bring the system back to normal behaviour.
Please use (as root) "ip neigh show", and "ip route list cache" to try to
track down any weird differences between the box when it is behaving
normally, and the box when wedged. You may want to compare it to a healthy
box on the same network segment.
You can also try to see if "ip route flush cache" and "ip neigh flush" can
unwedge the system. After a flush, "ip neigh show" and "ip route list
cache" should return very few, if any, entries.