Solution
It was found (here, and here) that Podman uses its own DNS server, aardvark-dns
which is bound to port 53 (this explains why I was able to bind to 53 with nc
on the host while the container would still fail). So the solution is to bridge the network for that port. So, in the compose file, the ports section would become:
ports:
- "<host-ip>:53:53/tcp"
- "<host-ip>:53:53/udp"
- "80:80/tcp"
where <host-ip>
is the ip of the machine running the container — e.g. 192.168.1.141
.
Original Post
I so desperately want to bash my head into a hard surface. I cannot figure out what is causing this issue. The full error is as follows:
Error: cannot listen on the UDP port: listen udp4 :53: bind: address already in use
This is my compose file:
version: "3"
services:
pihole:
container_name: pihole
image: docker.io/pihole/pihole:latest
ports:
- "53:53/tcp"
- "53:53/udp"
- "80:80/tcp"
environment:
TZ: '<redacted>'
volumes:
- './etc-pihole:/etc/pihole'
- './etc-dnsmasq.d:/etc/dnsmasq.d'
restart: unless-stopped
and the result of :
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
udp UNCONN 0 0 [fe80::e877:8420:5869:dbd9]:546 *:* users:(("NetworkManager",pid=377,fd=28))
tcp LISTEN 0 128 0.0.0.0:22 0.0.0.0:* users:(("sshd",pid=429,fd=3))
tcp LISTEN 0 128 [::]:22 [::]:* users:(("sshd",pid=429,fd=4))
I have looked for possible culprit services like systemd-resolved
. I have tried disabling Avahi. I have looked for other potential DNS services. I have rebooted the device. I am running the container as sudo (so it has access to all ports). I am quite at a loss.
- Raspberry Pi Model 1 B Rev 2
- Raspbian (bookworm)
- Kernel v6.6.20+rpt-rpi-v6
- Podman v4.3.1
- Podman Compose v1.0.3
EDIT (2024-03-14T22:13Z)
For the sake of clarity, shows nothing on 53, and
shows nothing listening to port 53 — the only listening service is SSH on 22, as expected.
Also, as suggested here, I tried manually binding to port 53, and I was able to without issue.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:
Fewer Letters | More Letters |
---|---|
DNS | Domain Name Service/System |
IP | Internet Protocol |
PiHole | Network-wide ad-blocker (DNS sinkhole) |
[Thread #602 for this sub, first seen 15th Mar 2024, 07:25] [FAQ] [Full list] [Contact] [Source code]
After checking that you can open port 53 udp yourself with, say, nc (which you tried), strace the binary that tries to open port 53 and fails, and find the system call that fails. You can compare it with an strace on nc to see how it differs.
If this doesn’t clue you in (e.g., you see two attempts to listen to the same port…) Next step would be to find in the source code where it fails (look for the error message printout) and start adding diagnostic printouts before the failing system call and compile and run your edited version.
Have you made sure Podman has access to 53? It runs as a local user
This post from Stack Exchange might help you, switching 80 for 53, of course.
What about using Docker image instead?