All the configuration examples I've been able to find for PIXes show NAT and PAT address pools being taken from the address range on the outside interface of the PIX. Is there any way to map inside addresses to a separate pool of addresses which could be routed to the PIX?
Background: we have an FWSM running PIX OS 3.1(x) and until recently we were exclusively using identity NAT (no translation) with a /29 on the outside interface. We now need to start doing NAT for a significant number of addresses. We have enough public addresses available to provide a large pool of outside addresses, say a /23, but I can't see a way to use them without readdressing the outside network and a corresponding break in service while I do it.