Interesting and quite a strange problem. Unfortunately I have no experience with an Aztech router, so no quick help there. I see it is assigning addresses in the 10.x.x.x. range. Most home DSL/cable routers hand out NAT addresses in the 192.168.x.x. blocks, but I don't think there should be any problem in your router using the 10. block (it's also a private block, but larger than many home routers can deal with, particularly with that 255.0.0.0 mask). I was asking about your being wired on the off chance that you got wireless working but were sometimes connecting to a router other than your own (I've seen it happen). No worry of that. The only thing that looks dubious is the 1500 MTU. With DSL you tend to encapsulate the packets and need to shrink the MTU a little (usually around 1492 max) for best throughput. But MTU is certainly not an issue for DNS resolution, which will happen with packets much smaller than this limit. You might want to do a netcardconfig and manually make the settings rather than let DHCP do it for you to see if that has any effect on the DNS problem, but I'm really running short of ideas.