Just wonder if you can give me an idea how to sort out a situation when I have 2 subsequent subnets of /29 bits each, one of them is "in front" of PIX515 (OS ver. 7.1) and the second is "behind". For some reason when I asked ISP to just specify external IP address of PIX as a gateway for second subnet on their router, I couldn't get things connected. However when I've asked to revert things back to what is was before (single /28 bits subnet behind ISP's router, in front of PIX) one of hosts behind PIX has suddenly started sending/receiving traffic through PIX. The other host with similar network settings (just next IP address, belonging to the same subnet as first device) still doesn't behave.
I know that PIX isn't a router, it doesn't work with IP headers, but I just need to know what exactly needs to be done on PIX/hosts/ISP's router to get subnet "behind" PIX routed through?