The Netopia units are meant to be a gateway/router so it will likely have its own Firewall, DHCP server, and NAT features enabled. You need to disable these things if you want to use this gateway as just a simple bridged modem.
What you mentioned about the router halfway working when you switch the ethernet cable from the WAN to LAN plug means your Netopia gateway is not properly configured yet. There is no way you could have the modem configured for bridging if you are connecting to the internet when the router is connected through its LAN port instead of its WAN plug. Assuming you are using PPPoE authentication to establish your DSL connection, the intellinet router would not be able to perform this function over one of its LAN ports. This scenario tells me you still have this turned on in the Netopia unit. Turn it off!! You could always forget about the intellinet router and just use the Netopia gateway since it is a NAT router also! Call Netopia. My experiences speaking with them on the phone has been a pleasant one. SBC wasn't much help at all when dealing with this equipment so I just talked to Netopia directly. They emailed me the 'feature key' files that were necessary to unlock some of the menus/settings in their equipment. I don't recall ever having to pay a fee for phone support. a couple more helpful links :) http://www.netopia.com/support/hardware/3341.html http://www.netopia.com/corp/contact_us.html