My original reason for asking this question was that entries appeared to stay in the ARP cache (up to 10 minutes) for much longer than the ARP cache timers seemed to indicate. I've since "discovered" the useful -s option to "ip neigh list". This helped me understand a little better. Here's my attempt to answer my own question. Is this accurate? An ARP entry is a candidate to be removed gc_stale_time seconds after last used. Garbage collection runs every gc_interval seconds which is when the entry can be deleted. However, an ARP cache entry will not be removed while there is a reference to it such as route cache entry. The ARP cache entry will move from reachable to stale state in the normal time but stays stale until the route cache entry is removed. The route cache may keep an entry for several minutes even with no traffic or sessions to that address. So after the route cache entry is removed, the reference to the ARP cache entry goes away. Then next time ARP cache garbage collection runs the entry will be removed. Paul Staniforth kuznet@ms2.inr.ac.ru wrote: > Hello! > > > ARP cache entries for which there has been no traffic timeout in > > several minutes. > > It is gc_stale_time, set to 1 minute by default. > > Alexey - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org
