Where can I find out how long ARP table entries are cached? I'm running 13.10. Can I get this on the command line?
21 Answer
You can get the default arp cache timeout by:
cat /proc/sys/net/ipv4/neigh/default/gc_stale_timeIn my case it's 60. That means 60 seconds until the entry is removed. Every time the entry is used in the table, the timer for this entry resets to 60 seconds.
Additionally you can set it by:
echo 3600 >/proc/sys/net/ipv4/neigh/default/gc_stale_timeOr permantent in the config file /etc/sysctl.conf.