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[Bug]: DNS queryA Fails

See original GitHub issue

👟 Reproduction steps

Setup a DNS Monitor using the default CloudFlare Resolver Server of 1.1.1.1

👍 Expected behavior

Monitor shouldn’t trigger as DOWN regularly when the actual domain’s DNS is resolving just fine.

To better diagnose the underlying problem I setup a nearly identical UK DNS monitor using Google DNS (8.8.8.8/8.8.4.4), and no UK incidents have been experienced seen since! The other added bonus - Google DNS seems to support ‘ANY/ALL’ DNS queries whereas CloudFlare does not, meaning we have a way to gather most of the DNS record types for the domain.

👎 Actual Behavior

UK frequently detects the domain’s DNS A record as DOWN with the message:

queryA ESERVFAIL domain.com

We have many A Record DNS Monitors in place for multiple domain names; experienced this across all of them.

🐻 Uptime-Kuma version

1.9.1

💻 Operating System

Ubuntu 20.04

🌐 Browser

Any

🐋 Docker

N/A

🏷️ Docker Image Tag

N/A

🟩 NodeJS Version

14.8.1

📝 Relevant log output

Up	2021-10-31 01:16:24	Records: 123.123.123.123
Down	2021-10-31 01:15:01	queryA ESERVFAIL domain.com
Up	2021-10-30 19:24:56	Records: 123.123.123.123
Down	2021-10-30 19:23:32	queryA ESERVFAIL domain.com
Up	2021-10-30 15:42:27	Records: 123.123.123.123
Down	2021-10-30 15:41:04	queryA ESERVFAIL domain.com
Up	2021-10-30 12:49:59	Records: 123.123.123.123
Down	2021-10-30 12:48:35	queryA ESERVFAIL domain.com

⚠️ Please verify that this bug has NOT been raised before.

I checked and didn’t find similar issue

🛡️ Security Policy

I agree to have read this project Security Policy

Issue Analytics

State:
Created 2 years ago
Reactions:1
Comments:19 (11 by maintainers)

Top GitHub Comments

1reaction

louislamcommented, Sep 12, 2022

I’m just wondering if they problem w/ the short names is that the cached dns record is shared over every monitor using the same connection options? Should that key be more complex (include the ID of the monitor for example)?

I don’t think so, because under same agent options, http agent is reusable. HTTP agent is not specified for only one domain.

You can see the example in https://github.com/szmarczak/cacheable-lookup#attaching-cacheablelookup-to-an-agent

And so far, I do not receive large amount of similar bug reports, so I assumed that it should be very specific issues like @ljurk said, he is using Windows DNS Server

1reaction

christopherpickeringcommented, Sep 9, 2022

I had a few other monitors one like this that started failing w/ the queryA ESERVFAIL and left the server rebooted. I left them and after 1 day they went away. There must be some other cache/matching that happens elsewhere causing it for me… I did reset the server dns cache (which is also probably what happened when the server rebooted).