RT-BE92U DNS Issues

[KiloCharlie]

Okay, I've had the RT-BE92U for a few months, and it was fine initially.  I switched ISPs a few weeks back, and about the same time I upgraded the firmware to the latest available at that time.   Man... it's been stupid since that time.  The issues initially seemed to start with WiFi clients suddently all dropping off once a day or so, requiring the router to be restarted.  This was the case for a couple weeks, until a new FW version came out (the latest to date) which I quick applied, hoping it would resolve my issues.

Much to my dismay, it made things worse.  Now I was dropping WiFi connections up to 2 times a day.  I began troubleshooting from a wired computer, running my logs through CoPilot searching for clues.  2.4Ghz was over utilized is what the consensus was, so I began tuning WiFi settings in hopes of reducing the utilization, which did seem to help some, but not enough.  Then 3-4 days ago, things got really bad.  Devices have been dropping every 2-3 hours, including wired devices.  My family is fuming.  I could no longer access the router through a wired connection, and I would have to power cycle the router to get things working again.  Something is wreaking havoc with this thing.

Tonight, I finally had some time, so I did a factory reset and rebuilt from scratch.  This time, only setting up one main WiFi network, and an IoT network.  Everything else I basically left largely untouched.  Once I got the basics configured I bagan testing and immediately discovered that I couldn't access any websites.  I quickly discovered that DNS queries from the clients were failing.  I double-checked my router WAN settings and confirmed that I was set to simply use the ISP DNS servers.  I tried a couple of the other built-in DNS server configurations, and even tried manually pointing to various public DNS IPs.  No change.  Nslookups from the router itself are working fine, however.  Go figure.

However, I manually set one of my clients to use 8.8.8.8 and DNS queries were successful.  The same was true when I set the DNS server to an internal PiHole server I had on the network, but was not currently utilizing.  I tried pointing the router to 8.8.8.8, 1.1.1.1, or adguard, but each configuration would result in the same result of DNS lookups failing on the clients.  

I then set the DHCP server on the router to advertise my PiHole server for DNS and this worked.

So what the heck is up with this router that it won't even pass DNS queries properly to the clients?  I haven't had it running long enough with this config to see if that might resolve my dropped client issue or not.  I'll see how the next 72 hours ago.  If it does, then my hunch is that this things is choking on passing DNS queries, and eventually just dies from the overload of pending queries.   I spent too much money on this thing to have such horrible issues.

[Alex52]

Turn off the 5GHz DFS Channel switch. This frees resources and speeds router function.

Use Smart Connect and assign 2.4GHz manually to a non-overlapping channel having the least interference.

Then, make sure the SSID authentication is WPA2/WPA3-Personal and Encryption is set to AES.

Last, reboot the modem and the router.

If this doesn't work, setup again without using Smart Connect.

[KiloCharlie]

I appreciate your suggestion, but this is not resolving the DNS issue.  As a test, I actually turned off the WiFi radio, and tested DNS queries through the router from the clients, but continued to receive no data returned.  This router is stupid.  So flawed.  My old RT-AC1900P and 68u routers were rock stars and provided me over a decade of great experience with the ASUS line.  This one, however, is a big dissappointment.  What the heck has happened to ASUS? I was curious if bumping up the be96u might be a better experience, but a quick google search indicates it's plagued with the same issues. 
Ugh... this thing is simply unusable in it's current state.   I can work around the DNS queries using the PiHole on my network, but I shouldn't be forced to do that.  And disabling a bunch of features to hopefully stabilize things a little bit is really stupid.   What am I paying for if that's what it takes?  I may be forced to abrubtly end my relationship with ASUS routers!  😞

[jzchen]

It'd be nice to know from which ISP to which ISP service you've changed to?  They don't all use the same DNS servers.  Also (strangely) there's a place for DNS in WAN and also DHCP server.  You might want to check that both match.  I still don't understand why this is so.

I have not been running ASUSwrt on my RT-BE92U node (to an EBG15 in AP mode, of all the models available,) but have been running Merlin.  I jumped over as I think the 2nd to (EDIT) latest firmware I saw 5 GHz signal disappear at times.  If you have Smart Connect enabled and 5 GHz disappears, I'm not surprised that 2.4 GHz is overloaded with clients.

Network Analyzer (by Jiri Techet) is what I use on my Android phone to help analyze the network.  I ended up quickly paying for the Pro version as it was economical to do so...

[Alex52]

This can also be a problem with your service provider's servers not responding to newer protocols. WIFI 7 BE routers enable and make use of IPv 6 where many providers use the older IPv 4 standard or a hybrid mix. IPv 4 is turned off by default now in favor of the higher security in IPv 6 in ASUS routers. Turn on IPv 4. The other changes I offered don't turn off anything you need. These units include Ai and freeing resources that aren't needed can allow Ai to start with features like self healing and correcting hidden switches. I've painfully gone through all of this myself and now have my own system working well. You can see this in the router logs once it starts. Ai can be a curse, but becomes a gift when it starts working with ASUS background updates you can only see being applied in the router logs.