i am setting a linux box as a firewall that connect directly to a cisco 1600 series router and breaks up the network into a dmz and trusted network zone.

the router lan port has a public ip 202.1.1.1.
the firewall internet port has a public ip 202.1.1.2.
the dmz nic has a public ip 202.1.1.3.
the trusted nic has a private ip 192.168.0.1 masquerading all traffic.

my problem here is after setting an ip route on the router stating that the gateway for 202.1.1.0 network is via 202.1.1.2 the dmz zone is not accessible from the internet but the trusted network has no problems accessing the internet and the dmz.

is this scenario a router or linux issue.

i have setup the forwarding rules properly.

can anyone provide any tips to configure a cisco router to function properly here if it is the router issue.