I have a network set up something like the following:

Device A <---> Router A <---> Router B <---> Device B

where Router A is a tp-link Archer AX73, and Router B is a tp-link Archer C7. Router B is flashed with OpenWRT, and Router A is using stock firmware. Router B is set up to be a wireless bridge between Router A’s network, and its own (it was set up using this guide).

What I am wondering is if Device A can find, say, Device B.local, using Avahi (assuming Device A, and Device B both have Avahi installed, and running), over this bridged network. So far, I haven’t been able to get it to work, so I’m wondering if it is possible at all. I have read that Avahi only works on a local network, but I was wondering if it could be bridged.

UPDATE (2024-01-16T01:28Z):

The issues that I mentioned in this post have since been solved. The majority of the issues stemmed from the fact that the relay software that I was using, relayd, doesn’t support ipv6. All the tests that I was conducting were defaulting to ipv6, so it was appearing like the bridge was failing unpredictably. Since that realization was made, and countermeasures were enacted, the problem was solved.

  • @theit8514
    6•11 months ago

    Avahi uses mDNS which is a multicast protocol. Multicast is designed to be link-local only: it ends at the edge of a broadcast domain. Router A would also need to bridge in order for that to work (i.e. Device A and B would need to have the same broadcast ip).

    On the other hand, there are ways of setting up Multicast Forwarding if the router supports it, or you could have a device in both networks that does Avahi/mDNS Reflection.

    https://www.cisco.com/assets/sol/sb/Switches_Emulators_v2_3_5_xx/help/250/index.html#page/tesla_250_olh/multi_forwarding.html https://serverfault.com/questions/121032/forward-mdns-from-one-subnet-to-another

    • KalciferOP
      1•11 months ago

      Router A would also need to bridge in order for that to work

      Why would Router A also need to be a bridge? Router B is configured to bridge its devices to Router A’s network, so, from what I understand, its devices are treated as if they are on Router A’s network – bridging is layer 2, and mDNS is layer 3 (afaik), so Avahi should be able to resolve across the bridge.

      On the other hand, there are ways of setting up Multicast Forwarding if the router supports it, or you could have a device in both networks that does Avahi/mDNS Reflection.

      Wouldn’t this only matter if Device A, and Device B were on two separate vlan’s?