After several hours of searching, unfortunately, I haven't been able to solve the following problem and hope someone can help me.
On the Server is Ubuntu 22.04 with docker, which provide multiple website-containers. Actually i get sporadically in syslogs Apr 2 10:39:32 vm1 dockerd[887]: time="2024-04-02T10:39:32.567669384Z" level=error msg="[resolver] failed to query external DNS server" client-addr="udp:127.0.0.1:57901" dns-server="udp:127.0.0.53:53" error="read udp 127.0.0.1:57901->127.0.0.53:53: i/o timeout" question=";domain.de.\tIN\t AAAA" spanID=f7a5101a1c0540080df traceID=5fc4ba54560e892a27a98b0566bc8c43194
The problem is that sometimes websites can't send emails, and websites take too long to load.
Another errorlog that i get:
> nslookup stackoverflow.com
Server: 127.0.0.53
Address: 127.0.0.53#53
Non-authoritative answer:
Name: stackoverflow.com
Address: 104.18.32.7
Name: stackoverflow.com
Address: 172.64.155.249
;; communications error to 127.0.0.53#53: timed out
;; communications error to 127.0.0.53#53: timed out
systemd-resolve/resolvectl contain no errors or warnings.
Adding the nameserver of google (8.8.8.8 8.8.4.4) to /etc/resolv.conf not helping. It also occurs even when only Docker is running and no containers are active. I feel like the issue disappears when I stop Docker.
Here is an example that shows how it suddenly works when I stop Docker:
root@vm1:/opt# nslookup askubuntu.com
;; communications error to 127.0.0.53#53: timed out
;; communications error to 127.0.0.53#53: timed out
^C
root@vm1:/opt# systemctl stop docker
Warning: Stopping docker.service, but it can still be activated by:
docker.socket
root@vm1:/opt# nslookup askubuntu.com
Server: 127.0.0.53
Address: 127.0.0.53#53
Non-authoritative answer:
Name: askubuntu.com
Address: 104.18.37.100
Name: askubuntu.com
Address: 172.64.150.156
