Problems with mDNS across VLANs
Problems with mDNS across VLANs
I'm using gateway ER8411 v1.0 (firmware 1.3.1) on software controller v5.15.20.20.
I have three separated VLANs:
- VLAN1: home devices (192.168.1.0/24)
- VLAN2: shared devices (e.g. printers) (192.168.2.0/24)
- VLAN3: work devices (192.168.3.0/24)
I would like the printers on VLAN2 to be discoverable on the other two VLANs and have setup mDNS accordingly on the controller. I can see with Wireshark that the mDNS requests and answers are transferred between VLANs, but as already stated here, the process seems to corrupt the packets so that the clients won't be able to discover the printers (discovery by a client works only if the client is on VLAN2).
Here is a mDNS answer I see in Wireshark from a printer I want to add when the client is on VLAN2 (the printer is correctly discovered by Windows 11):
And here is what I get if I am on VLAN1 with the mDNS repeater enabled (the printer is not discovered by Windows 11):
Notably, we are missing the "Additional records" where the IP address of the printer can be found.
Is any fix for this issue coming up...?
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@Clive_A
I have similar problems with mDNS as well on ER706W. It is not reliable at all. even though i followed the guide and set everything up. some mDNS forwards just don't get picked up on other VLANS and I can see them with wireshark being forwarded on said vlans.
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Pink_Waters wrote
@Clive_A
I have similar problems with mDNS as well on ER706W. It is not reliable at all. even though i followed the guide and set everything up. some mDNS forwards just don't get picked up on other VLANS and I can see them with wireshark being forwarded on said vlans.
This now seems to be a problem described in his comment.
The problem now seems to affect a few mDNS services instead of all.
We noticed his reports and issues on GitHub. We need time to confirm, diagnose, and possibly fix in the next firmware. Anyway, please wait for the future firmware and refer to the final firmware release notes.
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Can you provide the original Wireshark file that contains the interaction of the mDNS?
We would like to analyze this issue further
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I didn't keep the Wireshark output but I could make another one. I should be able to do so later today or tomorrow.
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Done. I added the requested info to the link I already shared with you via DM.
I'm also investigating another possible mDNS problem I observed while doing all my tests that would also be an Avahi bug. I'll post in another thread when I'm certain.
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I also had the idea to setup a CUPS server on VLAN2 and add my printers to it: there are no NSEC records published by CUPS, so mDNS forwarding is working flawlessly and it's much less hassle than patching Avahi with a work-around.
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