The TP-Link 1043nd shows multiple mac-addresses when is in service.
This causes the internet port to be disabled.
This problem can be solved by installing custom firmware, but this voids any warranty that you may have on the router. Also incorrect installation will cause the router to be unusable, so installing custom firmware should only be done when you have experience with that.
The custom firmware that we recommend is DD-WRT, because of the clear user-interface and standard correct settings.
User manual TP-Link 1043nd.