RT-AC88U Intermittent Loss of Internet Connectivity Despite Local Network Remaining Active

[MegaMango]

Hello Community,

I'm experiencing a perplexing issue with my ASUS RT-AC88U router and hoping you can help. I've had this router since 2017.

The issue is that all devices connected to the router intermittently lose internet connectivity, happening approximately every 2 hours, although this can sometimes vary with days of stability in between. During these periods, all devices report DNS errors and can't access the internet, yet they remain connected to the local network. Local networking activities (such as file sharing, local servers etc.) continue to work perfectly fine.

Interestingly, during these internet downtimes, the router itself maintains its connection to the internet. From the router's console, I am still able to ping, wget, and curl external sites.

As a temporary workaround, I have set up a script on a small server within my network. This script pings an external site continuously, and when it detects that the site is unreachable, it executes the 'service restart_wan' command via SSH. Upon running this command, internet connectivity is restored for the devices.

The router is running Merlinwrt 386.11 firmware. I have tried completely resetting the router, and even without any additional software installed (like Diversion, etc.), the problem reoccurs.

To summarize my troubleshooting efforts:

• Multiple restarts of the router.
• Complete reset of the router.
• Running the router without any additional software (like Diversion, skynet firewall etc).

Despite these efforts, the problem persists.
Does anyone have insight as to why executing 'service restart_wan' would temporarily resolve the issue?

Thank you in advance for your help.

 

[Ripshod]

From memory the RT-AC88U has problems with lan ports 5-8,which can cause all sorts of anomalies not restricted to those ports. It's always suggested to move devices from those ports to one of the first four, or add a cheap unmanaged switch if you don't have space.

 

[MegaMango]

For clarity, the issue I'm facing affects all devices, whether they are connected via ethernet or WiFi. None of them can access the internet during these periods of outage.

 

[degrub]

do you have anything connected to lan ports 5-8 ?

 

[Ripshod]

For clarity, faulty lan ports on 5-8 can affect any function on the router.

 

[MegaMango]

For clarity, faulty lan ports on 5-8 can affect any function on the router.

oh ok I got what you mean. No, only 1st and 2nd ports are in use

 

[Master3395]

I have the same problem with my RT-AC88U, I lose connection on ALL devices, except for LAN devices, they stay connected.
It happens more often than every 2 hours.
I have done all the steps mentioned in the first post, alongside I have also flashed the original AC firmware, I didn't have any issue with that, but I love asuswrt, but using it, I lose connection on both 2.4 GHz and 5 GHz, quite often.
Sometimes 2.4 GHz refuses connections from my device after a while.
If I restart the router, then everything seems to be fine for a while.

I am using LAN 1-4 (5-8 is empty)
It seems like i might be DNS attacked hm.

I have all 13-20 devices connected to both 2.4 GHz and 5 GHz at all times.
I also have an RT-AC66U as a repeater after this, and that device never had any issues like this.

Any suggestions?
@RMerlin

 

[Squall Leonhart]

try with rebind protection disabled.