Did you get it work? Although WAN port is unplugged, with DHCP disabled on TP-LINK router, your main router connected to its LAN by powerline adpaters will still work as the DHCP server in the...

Which one cannot be logged in? D7 or WR940N(RT)? When you cannot login, can you ping its IP address successfully? Upgrade latest firmware, reset the router to factory defaults and reconfigure it.

gav wrote Seems I understand what happened - internet provider changed the configuration and instead of external IP I get IP for their internal network. So I need to speak with them to get port...

Follow the guide below to check your configuration. If it won't help, submit a ticket to report the problem. http://www.tp-link.com/en/faq-444.html http://ticket.tp-link.com/index.php?/Tickets/Submit

Private IP Range: 10.0.0.0—10.255.255.255； 172.16.0.0—172.31.255.255； 192.168.0.0—192.168.255.255 How about your WAN IP? Is it static or dynamic? This external IP is differ than one I see in ipconfig...

Upgrade the latest firmware, reconfigure it and test if it works. http://www.tp-link.com/en/download/TD-W9980_V1.html#Firmware If it doesn't work, answer my following questions. W9980 is working as a...