We have a new machine that we have basically mirrored our checkpoint firewall on. It is the hardened SecurePlatform version based on Red Hat and it will replace the old machine.

I am about to test it. It will sit next to the old firewall machine for now.

Once I shutdown the old firewall and move the 2 cat5's to the new firewall and boot it up, I understand that the arp entires will be hosed up at first.

Is that something that will clear itself up after a few minutes, or do I need run the arp command with some parameter to get things set right again? Is there something I have to do on the Windows servers in our network?

Thanks....
(I'm new at this. but I ain't scared! )

Should just repopulate the arp table on it's own, but if you want to statically set the arp table, you can dump the contents to file, transfer file to new machine and then just have the arp table on the new machine load the file.