DNS Resolution host inside domain search cause problem

[Valentin Deville]

Hello,

Today i discover a issue on my docker installation.
For example, i need to resolve test.test.com, test.com is in my search domain (search test.com), an nslookup test.test.com work without any problem (from externel dns server). On the host machine work without any problem (nslookup, ping, curl etc..) but on container ping start after 3-4 secondes and http call too. nslookup work on container normally.
I think it an IPV6 problem, if i test in the container ping -4 test.test.com he start instantly.

Do you need more information to debug ?

Versions:
On ubuntu 18.04

Client: Docker Engine - Community
 Version:           20.10.2
 API version:       1.41
 Go version:        go1.13.15
 Git commit:        2291f61
 Built:             Mon Dec 28 16:17:32 2020
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.2
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.13.15
  Git commit:       8891c58
  Built:            Mon Dec 28 16:15:09 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.4.3
  GitCommit:        269548fa27e0089a8b8278fc4fc781d7f65a939b
 runc:
  Version:          1.0.0-rc92
  GitCommit:        ff819c7e9184c13b7c2607fe6c30ae19403a7aff
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Thanks

[Valentin Deville]

I'v change the domain search, same issue. When domain dont have AAAA record, he cause problem

[Valentin Deville]

For the moment, to fix this issue i'v added --dns option in my daemon.json. Same server, but with this no problem.