I have configured the pihole docker to have it's own ip address which is being used by my router as the DNS server. pihole is functioning as expected.

 

However, when the docker is running, the forwarded ports I have set up for apps like Plex or Overseer only work periodically. I can have my browser on the external IP and forwarded port, and if I refresh repeatedly, it will bounce between successfully connecting and failing to connect. I'm seeing the same behavior when using a site like canyouseeme.org to test the open port. As soon as I disable the pihole docker, this problem goes away and I am able to consistently access my server via the external IP and open ports. 

optimus-diagnostics-20230105-1723.zip

"Thou shalt read the f*cking manuals for the docker" 😁

 

"Pihole can't be used for UNRAID itself, only for other machines on your LAN".

 

The PiHole Docker is a nice but bad idea. Pihole belongs onto a seperate box (use a pi 🙂 ) because it serves things that are needed already at boot time or do not work if tunneled through docker ports (not reachable). So what you see is the effect of round robin dns. Your UNRAID box has multiple IPs (automatically, because the dockers and VMs each opens seperate nets) and if somebody asks for the address belonging to the UNRAID, it gets one from the list (exactly, it gets the NEXT from the list, restarting the list when it reaches the end. So your Pihole Docker SOMETIMES gets the right address and often gets one from the pool that it cannot reach.

 

This is more or less random to you because you cannot know who and when somebody/something asked for the name. you may check it from the shell by issuing "nslookup UNRAIDNAME" a few times directly one after the other. The resulting lists will be sorted differently each time, thats fine, but thats also is the docker's problem.

 

Aah, I forgot to explain why it works from a different box: The "external" DNS (or MDNS) entry for UNRAID only contains the real LAN addresses which are routable. So requests from other dockers like Plex or so are properly mapped to the correct one (check from the outside with nslookup too, only ONE address will be visible)

 

Edited January 6, 20233 yr by MAM59

Thank you for that explanation. I'm okay with running pihole on another device and will look into setting that up. I just felt like I had configured something incorrectly as it seems that a lot of people are using the pihole docker successfully with opened external ports