DNS-over-TLS - "broken pipe" errors

[ammnt]

Prerequisites

• [x] I am running the latest version
• [x] I checked the documentation and found no answer
• [x] I checked to make sure that this issue has not already been filed

Issue Details

• Version of AdGuard Home server:
  • 0.103.3
• How did you setup DNS configuration:
  • VPS
• Operating system and version:
  • Debian 9

Actual Behavior

Regardless of the client resolver sometimes I have a "broken pipe" error withins a few minutes. At this time, no one domain will be resolved for the network clients😤As I understood this error concerns only the DoT protocol.

Screenshots

Here is no verbose log screenshot:


But looks like DNS processing works fine and the records has returned:


Additional Information

I will try to catch this moment with verbose log. What other data will be needed to solve this problem?

P.S.: I had the same error with Stubby resolver. I am now using the built-in Keenetic resolver. Therefore, it's about the server part, not the client🤔

P.P.S.: There is no such error if I use NextDNS directly or if I use the DoH protocol🤨

Thank you.

[ameshkov]

I'd really like to see the verbose log

[ammnt]

@ameshkov, it happened again yesterday. The verbose log is attached. Please, look at what happened at 19:15 with the external.fhel4-1.fna.fbcdn.net host and its cname scontent.fhel4-1.fna.fbcdn.net.

As far as I understand, the server received records for these hosts, but due to handshake problems or something like that this information does not reach to the clients resolver😬

Thank you.

[ameshkov]

It just means that the client closed the connection so AGH just cannot write an answer.

Not sure why this happens, but I am pretty sure this is not an AGH bug.