Need help RT-AX88U Internet Status: Disconnected

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Variable

New Around Here
I need some help with an ASUS AX-RT88U router that seems to have stopped working. I have had this router in place and working fine for almost 1 year. Sometime in December, a firmware update occurred and it stopped working. No other setting was changed. It would cycle saying "Internet Disconnected," "WAN Unplugged," and "DHCP does not function correctly." At that time, I unplugged everything and restarted. Still nothing. I contacted my cable service provider and everything seemed to be fine there. I checked and swapped the cables to make sure they were ok. I was using an Aimesh setup and changed one of the nodes (RT-AC68U) to a primary and everything worked. I factory reset the AX88U and tried again. Still nothing. I called ASUS and we went through some additional trouble shooting steps including changing frequency from aggressive to normal, and still had no luck. At that time, ASUS rep said he thought it was a bad WAN port and set up a RMA. Today, I received a new RT-AX88U and plugged it all in and to my dismay, I got the same errors. Again, I unplugged and reset everything. I swapped cables. I swapped routers, and the AC unit immediately works. I'm at a loss. There is no way that I received another new router with a bad WAN port. This has to be a firmware or setting issue, but I can't figure out what it would be. I would appreciate any help or light that you may be able to shine on the issue.

Thanks
 

L&LD

Part of the Furniture
Try setting the WAN DNS settings manually to 1.1.1.1 and 1.0.0.1, or any other valid DNS provider you want.

You can also try cloning the MAC address too via the MAC Clone button.
 

Variable

New Around Here
Thanks for the advice. That didn't seem to work. I did notice that if I plug another router into the modem and then send that to the WAN port on the RT-AX88U, that it connects. Obviously, this isn't a good solution. Anyone know what would prevent it from connecting to the modem directly but allow it coming from and old router?
 

John Fitzgerald

Senior Member
Thanks for the advice. That didn't seem to work. I did notice that if I plug another router into the modem and then send that to the WAN port on the RT-AX88U, that it connects. Obviously, this isn't a good solution. Anyone know what would prevent it from connecting to the modem directly but allow it coming from and old router?

WAN TAB: Is the MTU field blank? It should be set stock at 1500. (scroll down to the bottom and don't forget to hit Apply)
 

Variable

New Around Here
I couldn't find a MTU field under WAN tab. I did make some progress. I now can get it to connect after enabling WAN aggregation. It shows an error on the cable that is supposed to be on LAN port 4 as my modem doesn't have this capability. Still not sure why it won't connect without this setting enabled.
 

John Fitzgerald

Senior Member
I couldn't find a MTU field under WAN tab. I did make some progress. I now can get it to connect after enabling WAN aggregation. It shows an error on the cable that is supposed to be on LAN port 4 as my modem doesn't have this capability. Still not sure why it won't connect without this setting enabled.

Left side: WAN, top tab "Internet Connection", scroll down all the way to:

InkedWAN MTU_LI.jpg

My number is specific to my ISP. Stock number is 1500. If the field is blank that maybe the cause of your issue. That field needs to have a number and can't be blank.

 

John Fitzgerald

Senior Member
Thanks for responding. I don't have that setting.
View attachment 29572

You are on Cable, what Country, what ISP provider?

Are you comfortable doing another reset? And upgrading the Firmware on the router to a different Factory build or RMerlin.

If the AX88U (secondary) is being run through the AC68U (primary), you have to reverse these.

You should straighten out the AX88U and leave the other one (AC68U) out of the mix until it's right.
You can't correct the AX88U while it is in service secondary running in Aimesh mode.
 
Last edited:

Variable

New Around Here
Ok, for some clarification, when I started troubleshooting I had plugged the AC68 into the cable modem and then into the AX88 to check the WAN port. Once that was done, I plugged the AX88 back into the cable modem. Each configuration I tested was followed by a reset. I have Cox Cable in the US. My current working configuration is cable into cox cable modem, CAT6 to WAN on AX88U. It only works if WAN aggregation mode is enabled. I does show an error where the second CAT6 should be plugged into the LAN 4 port since my modem doesn't have this capability. When I turn off WAN aggregation mode, it shows internet disconnected even though it still has the same CAT6 plugged into the WAN Port.
 

John Fitzgerald

Senior Member
Ok, for some clarification, when I started troubleshooting I had plugged the AC68 into the cable modem and then into the AX88 to check the WAN port. Once that was done, I plugged the AX88 back into the cable modem. Each configuration I tested was followed by a reset. I have Cox Cable in the US. My current working configuration is cable into cox cable modem, CAT6 to WAN on AX88U. It only works if WAN aggregation mode is enabled. I does show an error where the second CAT6 should be plugged into the LAN 4 port since my modem doesn't have this capability. When I turn off WAN aggregation mode, it shows internet disconnected even though it still has the same CAT6 plugged into the WAN Port.

From this new info, you should not be using WAN Aggregation:

 

SandmanXX

Regular Contributor
Have you changed out cables, just to test this? Weirder things have happened to me before, new cable or old. The cable from modem to router.
 

Variable

New Around Here
Changing the cables was one of the first things I did after resetting everything. I even changed the routers to make sure the cables were fine.
 

lucazh

New Around Here
I understand that I'm not using WAN aggregation mode in the right way. I'm saying that if you turn it off, it doesn't work at all. It says disconnected. If I could figure out how to make the standard way not show disconnected, I would use that.
Hello, I have the same problem with the AX88AU. Could you solve it? My name is Lucas and I´m from Argentina. Thanks a lot.
 

GOTPIT

New Around Here
I understand that I'm not using WAN aggregation mode in the right way. I'm saying that if you turn it off, it doesn't work at all. It says disconnected. If I could figure out how to make the standard way not show disconnected, I would use that.
I have had the same issue since an update in December. The only fix i've found was Merlin Firmware 384.19. Even today I tried out the next update 386.1 and the problem came back after the reboot. I've spent countless hours on the phone with ASUS and my ISP troubleshooting the PPOE settings and have yet to figure out the trick. Never thought to turn on WAN aggregation, I might try that next week, but would have the same issue as you. It's a bit frustrating that this expensive POS can't be updated without breaking my connection with my ISP.
 

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