I suppose you have a official ip network assigned to you... So you have a access-router in front of your firewall as well... You have to split your network into e.g.:
whole network 195.145.1.0/24 network1 195.145.1.0/25 network2 195.145.1.128/25 inside interface of your access-router: 195.145.1.1 routing entry on your access-router: 195.145.1.128/25 GW: 195.145.1.2 outside interface of your firewall: 195.145.1.2 dmz interface of your firewall: 195.145.1.129
Your clients/server within your dmz should be of the range from 195.145.1.130-254 with GW 195.145.1.129 With the PIX for 2 level design it should have 195.145.1.130 with GW 195.145.1.129
I suppose you have a official ip network assigned to you... So you have a access-router in front of your firewall as well... You have to split your network into e.g.:
whole network 195.145.1.0/24 network1 195.145.1.0/25 network2 195.145.1.128/25 inside interface of your access-router: 195.145.1.1 routing entry on your access-router: 195.145.1.128/25 GW: 195.145.1.2 outside interface of your firewall: 195.145.1.2 dmz interface of your firewall: 195.145.1.129
Your clients/server within your dmz should be of the range from 195.145.1.130-254 with GW 195.145.1.129 With the PIX for 2 level design it should have 195.145.1.130 with GW 195.145.1.129
Best Solution would be doing it with routing/subnetting.
You can make a smaller Subnet in front of your ASL and in DMZ a bigger one. (or..erm...many small ones)
But you need access/config-rights on the ISP Router.