I’m setting up a wireless router for a customer… ADSL works fine, but as soon as I plug the modem into the TP-Link wireless router (into the WAN port), I can get as far as the router, but not out to the internet.

After some juggling of devices, I notice that both router and modem use the 192.168.1.X address range. This shouldn’t be a problem, since the WAN port should be “isolated” by the router (via NAT), so that the router-side IP addresses do not conflict with the WAN/modem side IP addresses… and thus they can both use the same IP address range without any conflict.

I eventually setup the TP-Link to use a slightly different IP address range: 192.168.2.X, and at that point, it all works just fine.

I’m running a bit short of time, otherwise I would have had a close look at the NAT settings, & see if that was the source of the problem (but then most routers have NAT setup to avoid this type of problem anyway).

I wonder why tp-link routers are that little bit different?