RT-BE96U (Merlin) + Xfinity TG4482A (Bridge) - Periodic Internet Loss (every 3-4 weeks)

[random9]

I have an issue where, about every 3 to 4 weeks, my Internet connectivity stops working. The Asus router says No Internet Connection. This never occurred with my older RT-AC68U with Merlin firmware that I had used for years and only started about 3-4 weeks after replacing it with new Asus hardware.

The setup:

• Comcast Xfinity TG4482A modem configured in Bridge Mode
• Asus RT-BE96U with Merlin 3006.102.5 – configured Wan -> “DHCP query frequency” : Aggressive Mode.

Note: this problem did occur with prior Merlin firmware on this device – e.g., the problem is not specific to just the latest version. Just never occurred when I used the RT-AC68U.

I’m at a loss to troubleshoot this. When the problem occurs:

• Local connectivity on the network still works, but there is no means to access the modem, even by IP. The route to the 10.x network between the router and the bridged modem (to access the modem's web interface) is inaccessible.
• Power cycling the RT-BE96U is not enough. That does not resolve the issue.
• Power cycling the TG4482A modem is not enough. That does not resolve the issue.
• I have found that if I turn off both devices. Then, if I power on the modem, let it boot, and after, power on the router, everything comes up and starts working again.
• I did try a different ethernet cable, just in case, but it did not help.

For now, I have just changed the “DHCP query frequency” to Continuous Mode in hopes that it could help. In the meantime, are there any other suggestions?

Any ideas on what might be going wrong here? What can I capture in the future to better troubleshoot this?
Seems crazy that it all worked for years with the AC68U, but not the BE96U.

 

[KevTech]

Comcast is shutting down access to the gateway through the 10.0.0.1 IP address for security reasons.
What you have to do is allow access through the admin tool.
If you use continuous your MAC may end up blocked by Comcast DNS as you will be seen as a bot.

Allow Xfinity WiFi Gateway Admin Tool online access using the Xfinity app

Learn how to use the Xfinity app to allow or turn-off access to the Xfinity WiFi Gateway Admin Tool.

www.xfinity.com

 

[random9]

Comcast is shutting down access to the gateway through the 10.0.0.1 IP address for security reasons.
What you have to do is allow access through the admin tool.
If you use continuous your MAC may end up blocked by Comcast DNS as you will be seen as a bot.

Sorry if I was not clear. I have access to 10.0.0.1 when everthing is working, that is how I put it in bridge mode. Access to it only fails when I lose Internet access which is the primary problem.

 

[KevTech]

Have you tried just using the XB7 by itself as a test to rule out a hardware issue with the gateway?

 

[random9]

Have you tried just using the XB7 by itself as a test to rule out a hardware issue with the gateway?

I used the XB7 by itself for a while when I first got it, but that was a while ago. I use too many of the features in Merlin's firmware to go without it now. However, here is another data point: when this does happen, if I use the troubleshooting in the Xfinity app, it does indicate that my modem is live and reachable from their network. Given that I had been using the XB7 with my older RT-AC68U without any problems, and the problem first occurred about 3 weeks after the upgrade to the RT-BE96U, and then again about every 3-4 weeks after that: I don't feel it is a 'failed' hardware issue with the XB7.

That said, it could be a hardware/firmware compatibility issue between the two devices' chipsets. I'm not sure how to troubleshoot or resolve it if it is that.

 

[KevTech]

Comcast keeps updating and sometimes reverting the firmware on the gateway when it causes more issues.
Comcast pushes these updates during off-peak hours.
Unless you keep track of what firmware is on the gateway you could have had an update without your knowledge that is now messing things up.

 

[random9]

Unless you keep track of what firmware is on the gateway you could have had an update without your knowledge that is now messing things up.

Sounds like I should start tracking the comcast firmware vesion to see if there is a correlation. Still, I would have expected it to resolve by rebooting (full power-cycle) only the modem. Seems odd that the RT-BE96U could not recover.

 

[random9]

Exactly as predicted (4 weeks to the day) - I lost Internet again, so setting “DHCP query frequency” to Continuous Mode did not help.
This time, I tracked the version details eMTA & DOCSIS Software, image name, and advanced services on the Xfinity modem - They did not change (no obvious software update to the modem).

I'm really at a loss on how to troubleshoot and resolve this. It's very frustrating.

 

[degrub]

Do you get the same address from Comcast equipment each time ?
If so, as a test, can you set your WAN address static with that value ?

Also, as a test, you could purchase a TP-Link Omada or Ubiquity router and see if the issue repeats.
Or run in double NAT with the XB7.
Can you replace the modem with one of your own that is on the Comcast approved list ?

 

[degrub]

Another similar thread - Note his disabling IPv6 solution ?

https://www.snbforums.com/threads/wan-drops-every-20-mins-after-xfinity-did-some-overnight-maintenance.96377/

 

[random9]

Do you get the same address from Comcast equipment each time ?
If so, as a test, can you set your WAN address static with that value ?

Also, as a test, you could purchase a TP-Link Omada or Ubiquity router and see if the issue repeats.
Or run in double NAT with the XB7.
Can you replace the modem with one of your own that is on the Comcast approved list ?

Thanks @degrub!

I'm not sure what those other products would tell me. Per the original post, I did not have the problem with RT-AC68U...the problem only started when I upgraded to Asus RT-BE96U.

As for the address, I can start tracking that. I do know the address changes from time to time. I would be concerned setting it to static value, knowing that it could change, and I would then lose Internet. I also have a DDNS auto-update when the IP changes...

Double-NAT is problematic for me and something I actively avoid. Not only that, if the XB7 is not in bridge mode it would have to broadcast a different SSID. Xfinity locks the in-home Xfinity Stream to the SSID of the XB7 and not my actual internal network - family would not be okay with this...

I don't have another modem to try... but again, this modem worked perfectly fine with the RT-AC68U. Do we know if RT-BE96U does something different that could cause this?

Another similar thread - Note his disabling IPv6 solution ?

https://www.snbforums.com/threads/w...xfinity-did-some-overnight-maintenance.96377/

Interesting find, I'll keep an eye on that one too.

 

[random9]

Can you replace the modem with one of your own that is on the Comcast approved list ?

I arranged to upgrade the modem in hopes that may resolve it. I guess we will see in another 30 or so days. I'm starting to suspect that the problem is on the Xfinity side given the monthly cadence.