[RT-N66U] Router dropping internet connections sporadically throughout the day

[yokuyuki]

I've been battling an issue that has manifested itself rather suddenly with my old yet reliable ASUS RT-N66U router in that it will sporadically drop internet connections throughout the day.

Symptoms

• Drops for about 1-3 minutes and it'll come back as normal
• At the start of the outage, upload is the first to go so if I'm on a video/voice call, they won't be able to hear me or I'll come across garbled, but I'll be able to hear them and eventually everything will disconnect
• I'm still be able to log into the router admin page albeit it loads rather sluggishly and you can see that the CPU usage is up slightly (2-5%)

My Troubleshooting

• I know it's not my ISP as I'm hardwired to the router and when I switch to hardwiring to the cable modem, the connection will be stable for hours on end
• I've also already upgraded the firmware of the router to the latest and factory reset the settings after which it was stable for a week, but now it's back to dropping about 15% of the time
• I've swapped out the ethernet cable from the router to the modem
• I've checked the syslogs on the router and there aren't any obvious errors

One thing that I've been looking into is whether a bad power supply would cause the router to fail sporadically like that, but I also don't want to spend money on a new power supply only for the issue to be failing caps in the router itself. I was hoping that someone else has experienced similar issues like this before and had other thoughts.

 

[ColinTaylor]

Look for errors in the router's syslog.

 

[yokuyuki]

Look for errors in the router's syslog.

Forgot to mention that I did that already and no errors.

 

[K-2SO]

will sporadically drop internet connections throughout the day.

On both 2.4GHz and 5GHz bands?

 

[yokuyuki]

Both 2.4GHz and 5GHz bands?

Yes and even wired.

 

[K-2SO]

Yes and even wired.

This router runs hot. Any changes in room temp recently? Overheating?

 

[yokuyuki]

This router runs hot. Any changes in room temp recently? Overheating?

At first, I thought it might be overheating since it's winter and heat is turning on, but it's pretty chilly now and it's still happening.

Don't have cpu temps, but the radios are 2.4 GHz: 54°C - 5 GHz: 56°C

 

[K-2SO]

radios are 2.4 GHz: 54°C - 5 GHz: 56°C

This is normal. Any new devices on the network? Android phones?

 

[yokuyuki]

This is normal. Any new devices on the network? Android phones?

No new devices on network. I am running an Android phone, but it's not new.

 

[K-2SO]

No new devices on network.

What is your ISP speed? What do you mean by dropping? Lost packets or high latency?

 

[yokuyuki]

What is your ISP speed? What do you mean by dropping? Lost packets or high latency?

ISP speed is 300/20. Dropping as in high packet loss for a short duration for roughly 1-3 minutes.

In the last occasion, I noticed that it may also affect intranet as well as I couldn't see any of my cast targets on network during the outage.

 

[K-2SO]

I noticed that it may also affect intranet as well

Not very clear for me. Do yo see this on one device most of the time?

 

[yokuyuki]

Not very clear for me. Do yo see this on one device most of the time?

At the time, I was only checking on one device for cast targets on intranet, but the outage definitely affects all devices as I can see my phone drop off wifi due to lack of internet connectivity, my desktop is unable to resolve any addresses, and my laptop drops its VPN connection.

 

[K-2SO]

I see you already did troubleshooting. It is probably time to replace this router with a newer one and better utilize your ISP connection.

 

[yokuyuki]

I see you already did troubleshooting. It is probably time to replace this router with a newer one and better utilize your ISP connection.

That's what I was afraid. Thanks!

 

[L&LD]

What firmware are you using exactly? What are the CPU temps (the radios always run cooler)?

I would suggest flashing @john9527's RMerlin fork for your router and doing a full reset and then minimally and manually configuring it to connect to your ISP and secure your router.

I would also turn off both the router and the modem for at least 10 minutes and ideally an hour or more and then power up the modem, wait for it to settle for 5 minutes or more, and then turn on the router too.

 

[K-2SO]

What are the CPU temps (the radios always run cooler)?

No CPU temp reading on this router. I believe, he already runs Merlin. There no temps reading in Asus stock.

 

[yokuyuki]

What firmware are you using exactly? What are the CPU temps (the radios always run cooler)?

I would suggest flashing @john9527's RMerlin fork for your router and doing a full reset and then minimally and manually configuring it to connect to your ISP and secure your router.

I would also turn off both the router and the modem for at least 10 minutes and ideally an hour or more and then power up the modem, wait for it to settle for 5 minutes or more, and then turn on the router too.

As K-2SO has mentioned, there's no CPU temp reading on the RT-N66U. I'm already running the latest version of John's fork and did a full reset after upgrading to that.

I've powered both off before for some time and turned them on and it's generally more stable for a day or so after a power off, but after a while, it starts failing again.

 

[Chris313AllNight]

That's what I was afraid. Thanks!

If you end up needing to replace the router with new, you might wanna consider these:

Cheaper: https://www.amazon.com/dp/B0752FD3XJ/?tag=snbforums-20

I've used 86s in 2 different places to major great effect for 2 years now. No complaints. If you're a Gig or under and don't care about AX yet, this is something you should consider.

If you feel like giving AX a try, most here rave about the AX88U: https://www.newegg.com/asus-rt-ax88u-ieee-802-11a-ieee-802-11b-ieee-802-11g-ieee-802-11n-ieee-802-11ac-ieee-802-11ax/p/N82E16833320370?Description=Asus Ax88U&cm_re=Asus_Ax88U-_-33-320-370-_-Product&quicklink=true

Still limited to a Gig or under. But should make it a few years.

Both are also Merlin compatible if Merlin is what you like to use.

Be sure to return and tell us how it went. I'd like to know how you made out.

 

[K-2SO]

but after a while, it starts failing again.

If you like Merlin options, RT-AC66U_B1 model is ~$100. Equivalent to RT-AC68U. Good low cost upgrade to RT-N66U.