RT-AC88U + 3.0.0.4.384_20308 + IPv6 = not good

[Hunter Walker]

So this router had been performing beautifully since I bought it in December. We are a small business running on a Comcast 500/35. We don't have any crazy bandwidth demands though quite a few devices.

My dev needed IPv6 (Native with other settings as defaults) turned on so I did that two nights ago. I saw a couple hiccups yesterday in service, but figured it was Comcast as issues were reported in the area.

I also updated firmware last night.

Today, however, service degraded a lot. I log in to the router and see CPU Core 1 locked at 100%. I've never seen it anywhere close to that. This is after a full reboot this morning too.

Any ideas as to what I can do? I don't want to treat my users as lab rats testing this out, so it would be great to be able to test the solution on the weekend and be confident it will work come Monday morning when everyone hops on the network.

Screenshot of CPU Core 1 attached.

Thank you for your help.

 

[Gregory Phillips]

At a minimum turn it completely off with the physical power button and let it drain for a minute or so then reboot and see if it makes a difference. I think you need to reflash the unit judging by the firmware light at the top flashing when you are already running the latest version and if you do download the file manually and upload it from your pc to the router.

I haven't had any IPv6 issues with this firmware on any of my clients.

 

[Hunter Walker]

Thank you, Gregory. Are you referring to the exclamation point? I think that is a warning about the wireless encryption, but I don't have wireless turned on for this router. We have Meraki access points in place. Actually one of those threw a Bad DNS error a couple of hours after I updated the RT-AC88U's firmware.

Attached are the IPv6 settings I had on there. Any possible issues or tweaks to try?

 

[Gregory Phillips]

When you hovered your mouse over the exclamation point what did it say? As for your IPv6 settings I would get the DNS server address that you want to use and manually insert them into the settings. I don't use my ISP's DNS and use Google instead so I manually enter them into the settings.

 

[Hunter Walker]

yeah, good call on the DNS. I set those to Google DNS elsewhere in the router config, but didn't think about those here.

As for the exclamation point. Nothing happens when I hover, but the attached image appears when I click it.

 

[Hunter Walker]

As a follow-up: I made this change. I then saw I had Dual-WAN on. I forgot to turn that off in Dec. I was thinking I would use two Comcast connections for load balancing. It didn't work.

At any rate, I turned if off, the settings applied, but now the router is down and inaccessible via the web app or the iOS app. Guess I am driving into the office now. Pretty disappointing performance from this thing lately. Oh well.

 

[Gregory Phillips]

Unplug the second wan ethernet cable from the router or it will still cause problems even it you have it disabled in the settings. If you still have problems reset it and reenter them. I still think you have a bad flash and need to reflash it. I had to use Merlin's firmware to clear out some stuff in mine and after I flashed his into it I followed up with the stock asus firmware which worked right afterwards.

 

[Hunter Walker]

That might have been the issue, I'm not sure. I reset the router and restored the settings. Seems OK now, but I haven't turned IPv6 back on. I am going to try again in a couple of weeks as my dev doesn't need access immediately.

I am going to reflash the memory in a couple of weeks and try again. Thanks for your help.

 

[Gregory Phillips]

No problem and I hope it works out for you.