My upstream provider is changing IP blocks. They are presenting both blocks to the current port our PIX 501 is hanging off of. I would like to be able to facilitate a smooth transition between IP Blocks, so I would like to have both blocks available to be NAT'd back to my inside network. The current block works just fine but if I add a new IP and try to use that it won't work (I assume the old gateway won't route the new IPs). So is there any way to create a "virtual" (probably not the right term) interface on eth0 of the pix so I can start using the new block (at the same time I am using the old block)?