ASUS rtn66u 5GHZ wireless periodically malfunctions

[absolution]

Hi friends.

As the title says, my RT-N66U periodically kinda breaks. All devices connected to the 5GHz wireless still report that they are connected but they are unable to access anything on the LAN or WAN e.g. I am unable to ping any other device on the network from a device that's connected to 5GHz.
2.4GHz and ethernet functions completely fine when 5GHz breaks (but devices connected by 2.4GHz/eth cannot ping anything on 5GHz after 5GHz has borked).
A router restart, or waiting quite awhile (like 30 mins or so), fixes the problem.

The syslog doesn't seem to give much away.

For what it's worth, I am running the latest John's Fork + Diversion running on a USB. I've only recently started running diversion and the issue has been happening for at least as long as I've been using John's Fork, possibly longer but I honestly don't remember.

I attempted a clean flash last night:
- Flash latest John's Fork firmware
- Factory reset
- Hard factory reset
- Configure router
- Reboot and nuke jffs
- Copy scripts back to jffs

As mentioned above, 2.4GHz and ethernet works fine, even when 5GHz craps out so I can prod/poke the router but I honestly couldn't see anything that jumped out as being a problem.

Any tips on what I could check?

Thanks so much in advance!

 

[ColinTaylor]

Could be DFS. What 5GHz channel are you using?

 

[absolution]

Hi @ColinTaylor

Everything wireless-wise is set to its default, so auto for everything channel-related. But, the available options are 36, 40, 44, 48.
DFS is the thing that stopps interference with RADAR? Is that a problem in the UK (where I am based)?

 

[ColinTaylor]

DFS is the thing that stops interference with RADAR? Is that a problem in the UK (where I am based)?

Yes radar interference is a problem in the UK. But 36, 40, 44, 48 are not DFS channels so that's not the problem.

 

[absolution]

Good to know. Anyway, I figured I'd see something in the log if there was a clash with something like radar interference but I don't seem to be seeing that.

Thanks for the help BTW!

 

[L&LD]

You had performed a good reset until you copied back the scripts...

Do a full reset, format the JFFS partition on next boot, being sure to hit apply at the bottom of the page before you reboot. Reboot the router 3 times in the next 15 minutes, waiting 5 to 10 minutes between reboots.

Before you insert the USB drive into the router, be sure to format it on your computer with NTFS.

Now, after formatting it via amtm with a single partition, install the scripts manually and one (testing) by (testing) one (testing).

 

[dev_null]

...And pick a fixed channel. Sometimes the scanning for a channel can lead to lag (either real or perceived).

Do a channel environment scan to figure out which channel is least congested and set it to that channel.

(Interestingly, my EU-sourced N66U has many more channels than you list, including the DFS channels.)

 

[absolution]

You had performed a good reset until you copied back the scripts...

Do a full reset, format the JFFS partition on next boot, being sure to hit apply at the bottom of the page before you reboot. Reboot the router 3 times in the next 15 minutes, waiting 5 to 10 minutes between reboots.

Before you insert the USB drive into the router, be sure to format it on your computer with NTFS.

Now, after formatting it via amtm with a single partition, install the scripts manually and one (testing) by (testing) one (testing).

Hi @L&LD
Thank you for the info!
Why reboot 3 times? My method was kind of similar to yours up to that point (I think I may have rebooted twice, once asking the router to format jffs).

How come I need to format the memory stick as NTFS? I'd previously formatted it as ext3 on my server. Is that not OK?

I will give this ago but it will probably be tomorrow or Sunday as all of the formats and reconfigurations take quite awhile...

 

[absolution]

...And pick a fixed channel. Sometimes the scanning for a channel can lead to lag (either real or perceived).

Do a channel environment scan to figure out which channel is least congested and set it to that channel.

(Interestingly, my EU-sourced N66U has many more channels than you list, including the DFS channels.)

Hi @dev_null

I have picked a channel in the past as I figured it may have been some kind of interference. Despite picking a fixed channel, the problem kept happening...

Yeah so I was wondering about the available channels as well, it seems like a lot of other people have many more channels than I do...

 

[dev_null]

Hi @dev_null

I have picked a channel in the past as I figured it may have been some kind of interference. Despite picking a fixed channel, the problem kept happening...

Yeah so I was wondering about the available channels as well, it seems like a lot of other people have many more channels than I do...

I don't have any better suggestions than L&LD. Reformatting without restoring is typically the best way to go.

Interestingly, I used the N66U for years with Shibby Tomato, but then started getting issues such as those you're describing (loss of connectivity, unexplained hesitation and pauses, despite reported connectivity).

I figured heat had damaged the components, so moved on, first to a different brand, then back to Asus. After discovering there was a current Merlin firmware for the N66U, I flashed back to John's version just to test it on the N66U. Obviously with a full reset and manual update to the settings.

For me, all the prior behaviours went away: the router has been 100% stable as a guest AP and at my parents house as a primary AP. So a full reset might help. Good luck!

 

[absolution]

I was wondering whether there's physical damage to the 5GHz but fingers crossed there isn't...

Is the only difference between my reset procedure and L&LD's is that I did not reboot enough times and, I guess, copied my jffs scripts back.
Weirdly, I don't think any of my jffs scripts touch anything to do with wifi...

 

[L&LD]

Couldn't post these earlier, they may help.

Fully Reset / Best Practice Setup / More

About L&LD

Almost all L&LD Links

 

[absolution]

Thanks @L&LD
BTW, the scripts I need to copy back aren't anything installed from Diversion or amtm, they are a few small customisation scripts, such as a one line dnsmasq.conf.add script containing `address=/ddns/localip`

They way I reinstalled them (by copying them back) is the only way to install them. I don't know if that makes a difference or not...

 

[absolution]

Quick update: after reading through the various dox @L&LD sent over, I have not yet attempted another full factory reset (as it takes a pretty long time to do) but I noticed the suggestion of picking a completely new SSID and I've given that a go. So far, everything seems good. I did restart the router today but that was a precautionary measure as I had a big meeting and couldn't risk a router crap out.
Hopefully it stays solid. If this doesn't work then I will attempt another full reset and then really minimise the scripts I'm using on JFFS...

 

[absolution]

hmm looks like it happened again. Sad.

I guess I can try another full reset...

One thing I did notice was that the tx reported by my Mac completely plummets to 6 when the problem is happening. I don't know if that reveals anything at all?

 

[Tech9]

I noticed the suggestion of picking a completely new SSID

You use the same router with the same clients. No need to do waste your time with new SSIDs.

I guess I can try another full reset...

It may not help you. Replace this router with something fresher, RT-AC66U B1 is a good $100 upgrade.

 

[absolution]

You use the same router with the same clients. No need to do waste your time with new SSIDs.



It may not help you. Replace this router with something fresher, RT-AC66U B1 is a good $100 upgrade.

Hi @Tech9

Thanks for the advice.
The argument for changing SSID (as a test to see if that was problem) actually seemed pretty sound so I only lost a day or so.

Of course binning the router and upgrading is an option, and one that's becoming more attractive.
It's just that everything else with the router is still excellent. I was hoping to find out that the 5GHz wifi going wobbly was a software issue or misconfiguration. Then it could be easily fixed and I could get some more years out of the router...

 

[Tech9]

software issue or misconfiguration.

Could be hardware issue. Don't waste your time with multiple resets and reboots. If the router is not working properly anymore - replace it. It will stop working again when you need it most. This model is 10-years old now, many things may have happened inside in 10 years use. Nothing lasts forever.

 

[wh7qq]

Could be hardware issue. Don't waste your time with multiple resets and reboots. If the router is not working properly anymore - replace it. It will stop working again when you need it most. This model is 10-years old now, many things may have happened inside in 10 years use. Nothing lasts forever.

Nothing lasts forever but the RT-N66 is a robust router which even at 10 years is serving well in my network. It is not fast...N series...but otherwise good hardware. I'd be inclined to try a replacement power brick before getting a new router but my budget might be tighter than yours. Differing loads and conditions might pull the voltage down intermittently. Also, do a channel scan to see if neighbors are interfering. Try a different control channel. The SSID change isn't going to fix anything...but might help to confuse local hackers a very little bit.

By the way, John's Fork/Merlin firmware is always a good bet but if you are using the 380.xx generation of firmware (AsusWRT or Merlin) firmware, you may need to resort to the W$ based rescue utility or the CFE Mini Web Server to load it due to FCC requirements.

 

[absolution]

Nothing lasts forever but the RT-N66 is a robust router which even at 10 years is serving well in my network. It is not fast...N series...but otherwise good hardware. I'd be inclined to try a replacement power brick before getting a new router but my budget might be tighter than yours. Differing loads and conditions might pull the voltage down intermittently. Also, do a channel scan to see if neighbors are interfering. Try a different control channel. The SSID change isn't going to fix anything...but might help to confuse local hackers a very little bit.

By the way, John's Fork/Merlin firmware is always a good bet but if you are using the 380.xx generation of firmware (AsusWRT or Merlin) firmware, you may need to resort to the W$ based rescue utility or the CFE Mini Web Server to load it due to FCC requirements.

Hi @wh7qq
Thanks for the info.
Is there any way I could test the power brick to see if it is the problem without needing to buy a new one?
I have tried different wireless channels in the past and that did not help.

I am already using John's Fork so that's something I've already tested unfortunately...