D-Link router can't ping or reach DSL modem
"I'm helping my dad move to Earthlink DSL from dialup. As part of his package they sent a DSL modem (Zylink, or some brand like that) and I'm supplying a D-Link wireless router to act as the PC/modem go-between and to serve as a firewall. I used this same router at home before upgrading to a newer D-Link.
Problem: I cannot get the D-Link to speak with the DSL modem. Their respective IP addresses are 192.168.0.1 (D-Link) and 192.168.1.1 (DSL modem) but they won't communicate if I put an ethernet cable between them. The D-Link offers a feature to ping IP addresses you enter but when I enter the modem's address the D-Link says it can't ping it.
I've reset the D-Link to factory default settings but even so, I can't ping the DSL modem. I don't believe I have any firewall rules established that would prevent this--I've looked closely and compared with my current D-Link settings at home.
I can connect my dad's PC directly to the DSL modem, using the same ethernet cable the DSL modem and D-Link speak with, and he can surf the internet if we do this. (He can also ping the modem.) So all signals indicate a working line and DSL modem. Obviously however I'd like to get the D-Link between the PC and modem, for protection.
Dad's connection to Earthlink will be via dynamic PPPoE and I have his username and password ready to go. But if the D-Link can't reach the DSL modem that's a bit of a moot point.
Do you have any ideas what's preventing the modem and router from communicating? Thanks for any and all suggestions."