DNS resolve not responding

Website, Application, Performance DNS & Network
1

We are expereincing issues with some DNS records whose domains authoritative nameservers are Cloudflare’s. A record stops being resolved after AAAA record is requested from outside sources globally. For example the record www.lightsms.com here tested with one of the Telia’s publicly acessible DNS servers 212.59.2.2:
$ dig www.lightsms.com @212.59.2.2 +short
195.216.233.92
$ dig www.lightsms.com @212.59.2.2 +short
195.216.233.92
$ dig www.lightsms.com @212.59.2.2 +short
195.216.233.92
$ dig www.lightsms.com @212.59.2.2 +short
195.216.233.92
$ dig AAAA www.lightsms.com @212.59.2.2 +short
$ dig www.lightsms.com @212.59.2.2 +short
$ dig www.lightsms.com @212.59.2.2 +short
$ dig www.lightsms.com @212.59.2.2 +short
$ dig www.lightsms.com @212.59.2.2 +short
$ dig www.lightsms.com @212.59.2.2 +short
$ dig www.lightsms.com @212.59.2.2 +short

I would like to stress that the issue is global i.e. we are able to reproduce the issue with different DNS servers in different infrastructures and the issue is record-specific. For exmaple the record in the previous example www.lightsms.com has the issue, but lightsms.com does not.

Another example is api.evp.lt (this time without www):

$ dig api.evp.lt @212.59.2.2 +short
195.216.233.55
$ dig api.evp.lt @212.59.2.2 +short
195.216.233.55
$ dig AAAA api.evp.lt @212.59.2.2 +short
$ dig api.evp.lt @212.59.2.2 +short
$ dig api.evp.lt @212.59.2.2 +short
$ dig api.evp.lt @212.59.2.2 +short

The issue was noticed about 3 days ago. Would appreciate any help with this.

P.S. When testing with Cloudflare’s own DNS servers the issue does not manifest. It’s reproducible only through servers above.

2

I can’t reproduce with Cloudflare, Google, Quad9 or OpenDNS’ DNS servers on the above domain. Trying to use Telia’s DNS servers just times out for me but it looks like an issue with them. I’d contact their support, not sure what we can do here.

1 Like
3

Thank you, will do.

4

@Paysera just to check one additional thing - from a location where you are getting the failures - could you run these commands and share the output?

dig +trace example.com
dig @1.1.1.1 example.com
dig @8.8.8.8 example.com
curl example.com/cdn-cgi/trace
traceroute simon.ns.cloudflare.com

Replace example.com with the hostname(s) you are seeing the issue with.

5

Thanks, checking.
The problem is that 212.59.2.2 is actually non-public DNS (one of the largest though), which will respond only if you’re querying from Telia IP as a client.
But we can reproduce the issue on other BIND servers - I need an IP of the tester so we can whitelist.

6

In fact, just checked - it works absolutely fine with public Google DNS servers.
It’s more like a problem nationwide in our region, I think. Trying to reach out for Telia support.

7

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.