Switch outside your control with incorrect arp table?

home | blog | Teh Internet | guest blog |rants | placeholder | political | projects | Gwen and Liam | Citadel patched | Tools | Scouts


- Careful Chrome users, this search box might be "Not secure"



So you migrated an ip from one machine to another and in the process invalidated the arp table in the upstream switch that
you don't control

You can use arping with a broadcast on the new machine to invalidate the cache on the upstream (and other switches)


Thanks for the heads up Robert!

Some have -B for broadcast (see venerable man pages):
arping -S <ip> -B

actually, carp does it like this (iputils under Linux)
arping -q -I eth0 -U <ip>
---- update note ----
Later versions of arping under Ubuntu have used the -S, so they are in line with the BSD version.
Not sure if the package name changed, or just that utility, so be warned - and heck try either version...


If you are stuck on Windows, you could try Nmap like this:
Stolen from here http://serverfault.com/questions/69890/is-there-any-way-to-arp-ping-on-windows

nmap -PR -sP <host>


Also, an nice write up here:
http://www.ducea.com/2009/03/06/howto-force-remote-devices-routersswitches-to-refresh-their-arp-cache-entry-for-a-machine/




[æ]