Docker - use DNS IP other than 127.0.0.11 or specify a DNS server?

Support
1

Is there a way to specify the internal IP address that Vikunja uses. So it appears that by default, it is using 127.0.0.1. I was trying to debug why I was not able to get email notifications. So I was sending the test mail command in Docker. I was seeing this response:

time=2026-04-22T18:45:43.114Z level=ERROR msg="Error sending test mail: dial failed: dial tcp: lookup mail.****.net on 127.0.0.11:53: server misbehaving"

I’m not sure where the 127.0.0.11 IP is coming from. It looks like Vikunja is trying to use that as a DNS server since it’s pointing to port 53 but that’s not a valid IP on my network. I tried setting a DNS IP address in my YAML file, but that didn’t make a difference.

  vikunja:
    image: vikunja/vikunja:latest
    stdin_open: true
    tty: true
    user: "0:0"
    dns: 192.168.0.4
    environment:

It doesn’t seem Vikunja is using that or resolving the DNS. I had to put my mail server’s IP address in the YAML file instead. Now it’s not a “problem” as it won’t change, but it did force me to ingore certificate validation. So how can I get around this?

2

Hmm… Posted this a week ago. Does anyone who can support this software ever visit this forum?

3

Looks like no one who develops this software or knows much about it comes here? Kind of a bummer…

4

Hi NA9D,

I think the IPs you are mentioning are part of the internal Docker network, I suggest getting some help of ClaudAI or OpenAI Codex, I have had a lot of success setting up custom services in my homelab with Claude. I even managed to configure reverse DNS and valid HTTPS certs using Let’s Encrypt, this was a requirement of some specific projects I wanted to deploy.

I think the essence of your question is not related to Vikunja per se but more a generic understanding of Docker networking. (I assume here again that you are using Docker to run Vikunja)

5

Hmm that’s what I thought too but my docker container runs on a 172.29.0.0 address space not 127.0.0.0. I could understand if it was using 127.0.0.1 but 127.0.0.11? I see nowhere to change that…