I'm having an issue working with a PIX 7.0 that has lots of history. There is a ton of entries like below:
static (inside,outside) 192.168.1.0 192.168.1.0 netmask 255.255.255.0
I'm trying to make one ip address on that subnet come out as the firewall external IP. I have the global (outside) 1 interface set up with the nat (inside) 1 192.168.1.5. This doesn't work unless I pull out the static entry for the entire subnet.
The main problem I'm having is for some reasos when I pull out the static that has the subnet. Without the static entry the subnet comes out with an address other than itself. What does the PIX do for an address that doesn't have a static or global entry set up?
It would also need to be there if you had something like
global (outside) 1 x.x.x.x
nat (inside) 1 0.0.0.0 0.0.0.0
and you did not want 192.168.1.0 to be PAT'ed to x.x.x.x
Hope that makes sense, I don't know enough about your environment to know whether it is needed or not.