AX82U issues with WAN port going down every day

[mbender92]

Hello! At my wits end with an issue, hoping somewhere here can provide some insight.

Issue: My WAN port is going down roughly once a day at various times.

Temporary fix: Connect a computer to the WAN port and run dhcp release and renew commands, then reconnect the WAN port back to the modem and it will come right back online....

Hardware Details:
Router: ASUS RT AX-82U (v2 i think?)
Router Firmware: 3004.388.4_0-gnuton1 - I just flashed 3004.388.7_1-gnuton0_beta1 a few minutes ago but I don't see any change notes indicating this will fix anything. But figured id give it a shot.
Modem: Netgear CM1200 DOCSIS 3.1
ISP: Comcast

Note 1: Modem does not go down, can connect computer and still have internet access. This is solely an issue between WAN port on router and modem.
Note 2: Issue first occurred during an ISP service outage a few weeks ago, outage was resolved by ISP but my WAN port refused to come back up, resulting from issue described above.
Note 3: I have reformatted the router many times and my modem as well, although I do not believe it is an issue with the modem.
Note 4: I changed the DHCP query frequency from aggressive to continuous at one point which appeared to instantly resolve the issue. This has not resolved the issue since.
Note 5: I believe my router is v2 variant? But have been unable to find reliable information as to what the difference is between v1 and v2.

Any ideas what could be causing this issue? I am getting ready to RMA the router but i have a feeling this is resolvable. Please advise, thank you!

 

[Morris]

You could try NORMAL mode for DHCP. I suspect it's something else. My first suspect is the modem, cable modems like to break.

 

[Tech9]

Any ideas what could be causing this issue?

Not really. Many threads here on SNB Forums discussing similar issue, suspected Asus WAN issue in firmware, suspected modem incompatibility, suggested solutions from playing with GUI settings through modem replacement to router replacement or placing another router in front of the Asus router. For some reason it happens with specific ISPs perhaps on momentarily modem connection loss - the modem reconnects and continues working, but the WAN port hangs. RMA for Asus is unlikely to help.

One of the recent threads with continuation in another:

WAN Reconnect Problems Across ASUS Routers / Firmware Versions

Problem description: ASUS router sometimes does not attempt to reconnect WAN connection (or silently fails--nothing in log files) after outage even after modem comes back up. Steps to reproduce: Intermittent, so inconsistent. Disconnect modem and reconnect (unclear if manual modem disconnect...

www.snbforums.com

Solved - UPDATE: No longer required. See thread. - [Feature request] Option for DHCP Query Frequency Backoff Mode

Current options for WAN DHCP query frequency are: Normal: When router does not get a response from ISP, send another query after 120 seconds and make 2 more attempts. Aggressive: When router does not get a response from ISP, send another query after 20 seconds and make 3 more attempts...

www.snbforums.com

The OP solution was to replace the router with different make/model which works properly with their specific modem and ISP.