Cannot start docker container: net.ipv4.ip_unprivileged_port_start

[Killerbeast01]

Hello there!
Im trying to start the technitium container as usual (running it already for more than 6 month).
But today i updated my lxc container ubtuntu 24.04.
Since then i cannot start the container anymore with the following error:

⠹ Container dns-server Starting 0.2s Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: open sysctl net.ipv4.ip_unprivileged_port_start file: reopen fd 8: permission denied

I already tried setting

• cap_add: - NET_BIND_SERVICE
• privileged: true
• sysctl -w net.ipv4.ip_unprivileged_port_start=0
  but nothing seems to help.

Any suggestions?

[ShreyasZare]

Thanks for the post. It seems that the container is failing to start due to permission issues related to listening to port 53. I am not really sure about this issue and its seems to be container specific config issue. I would suggest that you post this on reddit.com/r/technitium community so that someone with experience with this issue may help you.

[stratself]

Are you running Technitium as Docker inside LXC? I found this issue which may be relevant

opencontainers/runc#4968

There also seems to be updates to LXC/Proxmox that solved this issue too