I'm sure you will need more details but I don't really know where to begin so I'll just state the apparent problem at this point.
I am getting ISP service through an Earthlink supplied Zyxel P-600 transceiver. I can make a direct Eathernet cable connection to this box and can reach it's management screen, etc. It is using IP address 192.168.1.1. In this mode it all works fine.
Alternately, I can directly connect a Zyxel P-300 series wireless router to the Eathernet port and successfully communicate with its management functions. It is set up to use IP address 192.168.1.2.
When I connect the transceiver to the designated WAN port on the router I find that I cannot communicate with either unit. If I run ipconfig /renew I get a message: DHCP Server unavailable.
I've experimented with few random things with no effect. Not being familiar with networking I don't know where to start looking. My guess is that this has a simple explaination. I hope so as I need this resolved fairly quickly.