fix arp caches

so yeah. your ipv4 forwarder may be all scrambled and you've flushed the arp cache per a previous post, but the switches still have the incorrect arp information and hilarity ensues. an easy way to fix this is to issue a network command from the machine affected by arp nastiness. here's a quick oneliner to use ssh to connect to somewhere else - in this case via an ip'd secondary nic:

ssh -b secondary.nic.ip.address -p port me@somewhere

and the arp cache up the switch stack's been updated. of course, you're connecting to another system that's hanging off another switch up and around the stack, right?