We've had a Linksys WRT54GS broadband router that we use as a wifi access point.
This is connected to a network switch which connects to a Netgear firewall FVS318 which connects to a D-Link ethernet modem. The Linksys has a fixed IP (192.168.0.250) on the Internal network and picks up a external IP from the D-Link automatically.
Now we cannot connect to the Internet using the wifi.
We can ping the local devices (192,168.0.x) from the Linksys but not the D-Link 192,168,1,1