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Hello everyone.

I've got a weird problem with an Archer C5400EU V1.0

I've got this router connected after the IT provider proprietary router (that is hooked up to the WAN port of the 5400). On the LAN side, I've connected PCs, printers, and so on.

Well, everything worked OK untill, all of a sudden, the router stopped working. The WAN led turned yellow and a direct ping resulted in 'no reply'.

First thing I tried was replacing the 5400 with an old TD-W8970, configured the exactly same way, and everything worked flawlessly, so it seems that cables or peripheral failures shouldn't be the issue.

Next step was a factory reset and a FW upgrade, then reload the saved configuration (that has worked for months) and try tu put back the C5400. Same problem, no WAN and no ping reply. I started a Wireshark session on the PC and noticed that ARP request from the desktop computer to the C5400 went unanswered, and the packet counter on the network interface property form in Windows 7 showed no return packets.

In the end, I put back the TD-W8970, changed the LAN IP of the C5400 connected it on a switch port, ending up with a 350 $ AP that (guess what) works quite well, up until now.

Does anyone has an idea of what the problem could be ? Could be the C5400 is faulty, in some way ?

Any help is appreciated.

Thanks

Paul