arp

manipulates the kernel's ARP cache in various ways. The primary options are clearing an address mapping entry and manually setting up one. For debugging purposes, the arp program also allows a complete dump of the ARP cache.

arp -a

Get a list of the arp table.

Notes

arp -d doesn't work on the arp on linux, freebsd or solaris. There isn't a command that deletes every arp entry on linux or solaris, but freebsd does allow you to delete all arp entries with 'arp -d -a'.

for i in `awk -F ' ' '{ if ( $1 ~ /[0-9{1,3}].[0-9{1,3}].[0-9{1,3}].[0-9{1,3}]/ ) print $1 }' /proc/net/arp` ; 
do arp -d $i ; 
done