mDNS resolution stopped working within last month

1st Official Post
    • New

    Hello,


    I have recently realised that mDNS resolution is no longer working on my NAS. As a result, the scheduled print job I have set up to keep my printer from drying out can no longer find the printer. I am not sure if the error comes from debian, armbian or omv. In this time debian 12.8 update landed. `avahi-browse` finds the machines, but `ping` or `ssh` do not. I tried running `omv-firstaid`and reconfiguring the network but it did not help either. Here is the output of `resolvectl status`:

    And here is nssswitch.conf:

    Allegedly libnss-mdsn and systemd-resolved can interact in mysterious ways but I am not sure where to look next. Any help is appreciated.

    • New

    Doesn't look like it has helped. I ran the command above, rebooted the NAS and it still cannot resolve the .local mDNS names. Strangely enough, my Android phone, my laptop and my desktop (latter two running Fedora 41) can all resolve mDNS names, including the one of the NAS. What I have noticed, however, is that when I ping odroidxu4.local from my laptop, the hostname being shown is odroidxu4.fritz.box. I have switched ISPs recently and now have to use fritzbox as a router. Could it be that it's builtin DNS server interferes with mDNS, and Fedora can deal with it whereas Debian cannot?

    • New

    This fritz.box domain name could indeed be the culprit. Unfortunately, there seems to be no way of turning this off. Here is the nmap output from the laptop:

    Code
    $ nmap -sP 192.168.0.0/24
Starting Nmap 7.92 ( https://nmap.org ) at 2024-11-29 21:52 CET
Nmap scan report for fritz.box (192.168.0.1)
Host is up (0.0041s latency).
Nmap scan report for odroidxu4.fritz.box (192.168.0.14)
Host is up (0.0033s latency).
Nmap scan report for snowball3.fritz.box (192.168.0.21)
Host is up (0.00072s latency).
Nmap scan report for raspberrypi.fritz.box (192.168.0.245)
Host is up (0.0078s latency).

    This is from the desktop:

    Code
    $ nmap -sP 192.168.0.0/24
Starting Nmap 7.92 ( https://nmap.org ) at 2024-11-29 21:55 CET
Nmap scan report for fritz.box (192.168.0.1)
Host is up (0.00039s latency).
Nmap scan report for odroidxu4.fritz.box (192.168.0.14)
Host is up (0.0019s latency).
Nmap scan report for napoleon2.fritz.box (192.168.0.68)
Host is up (0.00018s latency).
Nmap scan report for raspberrypi.fritz.box (192.168.0.245)
Host is up (0.0024s latency).

    And this is from the NAS:

    Code
    $ nmap -sP 192.168.0.0/24
Starting Nmap 7.93 ( https://nmap.org ) at 2024-11-29 21:55 CET
Nmap scan report for fritz.box (192.168.0.1)
Host is up (0.0016s latency).
Nmap scan report for odroidxu4.fritz.box (192.168.0.14)
Host is up (0.00030s latency).
Nmap scan report for raspberrypi.fritz.box (192.168.0.245)
Host is up (0.0011s latency).

    So it looks like Fedora systems can understand that foo.local is the same as foo.fritz.box and still resolve it, but OMV cannot. /etc/nssswitch.conf files differ somewhat. Fedora:

    OMV:

    • New

    I would say the issue you have is with the lan/network config on your new router. I have never used a fritz box but I have heard they are good.


    I have had many years of fighting with mDNS as I mainly use apple devices and they are a real pain. This is what I would do:


    1. look at fritzbox LAN settings and find where the domain is set to fritz.box - change this to something you are happy with but not .local (I use .lan)

    2. look at the fritzbox dhcp settings to make sure you are happy

    3. set a reserved dhcp ip for the nas server (give it the address you want omv to use)

    4. in OMV gui set network domain to .lan (or whatever you choose but not .local)

    5. in omv gui network - set static ip with the same ip deets as your dhcp reserved. make sure you use fritzbox gateway ip as dns server


    reboot. friztbox. reboot omv.

    • New

    jata1, it looks like router setting the domain to fritz.box cannot be disabled.


    In the meantime, I have checked what my rpi running Raspbian 11 is doing. It can too resolve mDNS names, which makes router causing trouble increasingly unlikely, given that 3 devices can work with .local hostnames and one cannot. But then Raspbian 11 does not use systemd-resolved.

    I will try downgrading systemd-resolved to see if it helps.

    • New

    I have 4 omv servers on my network - and they are across a range of architectures (arm64, amd64) and I have 2x rpi. They are all working correctly with mDNS.


    I had issues (mainly with apple client devices) for a long time. I fixed this by building my own opnsense firewall/router and had not one issue since I did this. Best solution 100%

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