I just ran across this method for remotely forcing a gateway to flush an
arp entry when you move IP addresses around.
1) Download/install “arping” from the following URL. System will need
libnet-devel and libpcap:
http://www.habets.pp.se/synscan/programs.php?prog=arping
2) Run this command: arping -c 1 -S a.a.a.a b.b.b.b
Where “a.a.a.a” is the IP you’ve moved, and “b.b.b.b” is the gateway IP.
Run this from the server to which you moved the IP. This should force
the gateway to flush its arp entry for that source IP.