Hey all. I’m hosting a Docmost server for myself and some friends. Now, before everyone shouts “VPN!” at me, I specifically want help with this problem. Think of it as a learning experience.

The problem I have is that the Docmost server is accessible over internet and everyone can log on and use it, it’s working fine. But when I try to access over LAN, it won’t let me log in and I am 99% sure it’s related to SSL certs over LAN from what I’ve read.

Here’s the point I’ve gotten to with my own reading on this and I’m just stumped now:

I’ve got an UNRAID server hosted at 192.186.1.80 - on this server, there’s a number of services running in docker containers. One of these services is Nginx Proxy Manager and it handles all my reverse proxying. This is all working correctly.

I could not for the life of me get Docmost working as a docker container on UNRAID, so instead I spun up a VM and installed it on there. That’s hosted at 192.168.1.85 and NPM points to it when you try to access from docmost.example.com - that’s all dandy.

Then, I installed Adguard Home in a docker container on my UNRAID server. I pointed my router at Adguard as a DNS server, and it seems to me that it’s working fine. Internet’s not broken and Adguard Home is reporting queries and blocks and all that good stuff. So that’s all still working as it should, as far as I’m aware.

So, in Adguard Home I make a DNS Rewrite entry. I tell it to point docmost.example.com to 192.168.1.80, where NPM should be listening for traffic and reverse proxy me to the Docmost server… at least I thought that’s what should happen, but actually nothing happens. I get a connection timed out error.

I’m still pretty new to a lot of this stuff and have tried to figure out a lot of things on my own, but at this point I feel stuck. Does anyone have advice or tips on how I can get this domain to resolve locally with certs?

I can provide more info if needed.

Cheers all!

Edited 19 April 2025 to add: Thanks for all the tips and suggestions everyone. I’m not 100% sure I fully wrap my head around what was going on here, but I did end up getting something working. I am going to continue looking into alternative solutions if only for educational purposes.

For anyone in future land who stumbles on this looking for help with a similar issue…

I’m not 100% sure what did end up fixing the issue, but I’ll remark on some things I did here. Check my comments in threads below to see troubleshooting steps and advice from others.

This bit is specific to Docmost itself, but I ended up switching the APP_URL variable from https to http. This change allowed me to login to Docmost over LAN using the IP:Port of the service itself, though my browser was of course warning me that the connection was not secure.

It may be just because I restarted my PC between tries, but upon trying it again tonight, the domain resolved when I entered it into my browser… but the issue now was that it was just going to the UNRAID login page rather than getting proxied by Nginx (which as a reminder, runs in a container on UNRAID system).

So I decided to spin up a different Nginx Proxy Manager container running in a VM on a different local IP, and pointed my Adguard Home DNS rewrite entry to that IP instead of the UNRAID system. Once I configured the NPM at that IP to proxy the address to Docmost’s IP:Port, voila! It worked! My friends were able to access Docmost at docmost.example.com and I was also able to access it at the same URL on my local network, and we were using the service simultaneously without issue.

  • Opisek@lemmy.worldEnglish
    2·
    2 days ago

    Not two A records. From what I understand, OP has an A record pointing to their public IP address (which Nginx is listening on behind a NAT). Then, on the local network, OP uses their own DNS server to ignore that entry and instead always serve the local IP when a host on the LAN queries it.

    Aside from OP’s devices potentially using a different DNS server (I was only able to solve it for my stock Android by dropping outgoing DNS in my firewall), this solution is a nightmare for roaming devices like mobile phones. Such a device might cache the DNS answer while on LAN or WAN respectively and then try to continue using that address when the device moves to the other network segment.

    These are the most likely scenarios in my opinion - OP’s devices are ignoring the hacky DNS rewrite (either due to using a different DNS server or due to caching) and try to access the server via the public IP. This is supported by the connection timeout, which is exactly what you would see when your gateway doesn’t do loopback.

    • Ashley@lemmy.caEnglish
      31·
      14 hours ago

      It’s called split horizon dns and it’s not that bad/nightmarish.

      • Zeoic@lemmy.worldEnglish
        2·
        11 hours ago

        Yeah, you are 100% right. Not only is it not bad in any way, but it is how nearly every single company with internal resources works… It is incredibly common.

    • iAmTheTot@sh.itjust.worksOPEnglish
      2·
      1 day ago

      Couldn’t I troubleshoot this by using a different browser, or even incognito mode? Because when I do that, it still times out. I appreciate the explanation and advice. I’m not too worried about it at this stage only because my service I am trying to get working, Docmost, will really only be accessed from my desktop. Plus, as I said in OP, I am enjoying learning about this stuff and want to figure out why this specifically isn’t working for educational purposes, even if I switch to a different solution.

    • fishynoob@infosec.pubEnglish
      2·
      2 days ago

      I didn’t think of that. Indeed, DNS caching/using different DNS servers for different devices will break it exactly like what OP is experiencing. Thanks.