LB1120 intermittent DNS issue

[verge999]

My LB1120 worked flawlessly for around 6 months, but recently has begun to exhibit odd DNS behavior around twice a day.

At those times, open sessions (VNC, video and audio streaming, etc.) will continue to work, but any new DNS requests time out.

I can get to the LB1120 interface and restart it, and then everything works again.

I have tried factory resets, and even stopped using it in bridge mode to see if that helped, but it was the same.

Any assistance will be much appreciated...

[bkibler]

I have the exact same problem.  DNS typically works for about 6 hours (although sometimes as short as 2 hours), and then stops working.  I can work around it by forcing my laptop to use a dedicated DNS server, but that's really annoying, and I'd just like DHCP to work properly through the router.  Or I can reboot the router, and then it works again.  Doesn't appear to be a hardware problem, as bypassing DNS works.

[verge999]

Interesting.

What dedicated DNS server do you use?

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@bkibler wrote:

I can work around it by forcing my laptop to use a dedicated DNS server

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[Blanca_O]

Hi @verge999 and @bkibler

Please describe your network setup. 

Kindly access LB1120 Settings page, in the upper right corner, click the About link and provide the following information: 

Firmware version 
App version
PRI version 

Regards, 
Blanca 
Community Team

[rsquaredg]

I have a pair of LB1120 cellular gateways using AT&T sim cards.  Both of them dump DNS periodically.  Sometimes I can go a whole day or two but other times I have to restart them several times in a day.  I have a load balancing configuration with a Ubiquiti USG router that has 2 WAN ports.

When DNS goes down they won't resolve new addresses.  If I am streaming from a radio station or other continuous source it will keep playing but no other web sites will work until I restart the LBs.  I am thinking this is AT&T's way to get me off their network.  I do use quite a lot of data and don't have any other provider choices.  No cable and no DSL where I live.

I've bought a couple of different connection monitoring outlets to try to auto reboot but this doesn't work because they are basically ping engines and when DNS quits resolving pinging remains just fine.  Any thoughts on how to solve this probelm are most appreciated.  My next step is to write a monitoring script to run non-stop on a Linux test box I have on the network and use it to trigger the outlet reboots when it can't resolve DNS via HTTP.

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@Blanca_O wrote:

Hi @verge999 and @bkibler

Please describe your network setup. 

Kindly access LB1120 Settings page, in the upper right corner, click the About link and provide the following information: 

Firmware version 
App version
PRI version 

Regards, 
Blanca 
Community Team

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I

[verge999]

A bizarre update:

The issue appears to have resolved on its own (exactly the way it arrived).

A few days ago the Internet from the 1120 became too slow to do much for about 90 minutes. My VNC session was nearly unusable during that time.

I tried a different 4G LTE hotspot (still AT&T) and got the same result.

Then it cleared up. And the ongoing issue form the last 6 months or so went away with it.

It took me a couple of days to believe it, but I haven't had any issues since then.

My best guess is that the issue was really with a local cell tower that ifnally got resolved by the provider.

Any other theories or thoughts are welcome...