systemd-resolved does not try other DNS servers if the first server returns REFUSED

[andreyv]

Submission type

• Bug report
• Request for enhancement (RFE)

systemd version the issue has been seen with

systemd 231

Used distribution

Arch Linux

In case of bug report: Expected behaviour you didn't see

systemd-resolved should try the next configured DNS server if the first server fails.

In case of bug report: Unexpected behaviour you saw

If the first configured DNS server returns a REFUSED reply to a query, systemd-resolved does not try the configured second or third DNS server, and instead fails to resolve the name.

In case of bug report: Steps to reproduce the problem

• Set up /etc/resolv.conf:

  nameserver [address of the refusing server]
  
  nameserver 8.8.8.8
  
  nameserver 8.8.4.4

• Start systemd-resolved
• systemd-resolve google.com outputs

  google.com: resolve call failed: Could not resolve 'google.com', server or network returned error REFUSED

[poettering]

Hmm, I figure we indeed should not consider REFUSE fatal for the full lookup.

[halvors]

Yeah, if possible it should try both servers, if one goes down, keep track of that so that the host know that it may not respond and to use the other instead.

[poettering]

Fix waiting in #5276.