multicast-relay VS udm-kernel

Like a lot of people with devices on different VLANs, I have been running scyto’s multicast-relay container on my UDM SE. With podman no longer an option on 3.0.13, I’ve been looking into running it on a raspberry pi as Ubiquiti’s MDNS solution never worked well for me. I found these instructions and was able to successfully deploy the container. Things are working as expected so I’ll probably end up upgrading to v3 soon.

multicast-relay container

for example i create my fixed function images like this example https://github.com/scyto/multicast-relay (look at the dockerfile)

I got it to work by running https://github.com/scyto/multicast-relay. I can't find the guide I originally used, but here is one that might get you started. I'm really only using it for the sonos discovery relay (I run the container with --noMDNS), but I do have a working system. I can run the sonos app on my phone (on my main VLAN) and it discovers and controls sonos devices on the IoT VLAN.

I struggled with this for a long time and tried all the solutions I came across, only thing that fixed it was to run the multicast-relay docker container on the UDM. I found that most of the solutions were aimed at the USG WHO’s had more customizable firewall rules. PS: you need to use podman which is the docker(ish) equivalent found on the UDM. Just replace “docker” with “podman” in all he commands

Turns out, the UDM-Pro supports dockers, which are containerized applications. So something like the multicast-relay docker would be a good solution for your Sonos gear.

#1 is relatively easy to accomplish with third-party tools, namely Scyto's multicast relay along with Boostchicken's UDM utilities. These tools have been available for a while now and many of you will already be aware of this approach and how it differs from the mDNS *reflector* offered by Unifi. It has more in common with the mDNS *repeater* approach of UI's EdgeOS. However, I've still been totally unsuccessful in relaying mDNS/SSDP across a site-to-site VPN between two UDM-Pros (or is that UDMs-Pro?)

I did have issues with the builtin mDNS (my GF's Samsung phone couldn't cast to Chromecast devices). I have setup boostchicken's udm-utilities along with scyto's multicast-relay, essentially following these instructions. I also use the udm-utilities to make manual DNS entry updates (cnames).

and this docker container: https://github.com/scyto/multicast-relay

the udm pro is good to about 650mbps. Cake here: https://github.com/fabianishere/udm-kernel

Arguably smart queues or preferably cake ack-filter on just the outbound 40mbit on the udm pro will be a mite better than PIE in many scenarios but that would take benchmarking. cake for the udm pro is available here: https://github.com/fabianishere/udm-kernel

https://github.com/fabianishere/udm-kernel is apparently 4.19 based

This is not the most serious deficiency, but perhaps a more robust solution is possible. It has recently become possible to swap out the kernel of a UDM to a custom kernel which permits us to enable igmpproxy. The developer also provides instructions on how to get a multicast relay working, but I've been unable to successfully apply them to allow discovery of a Chromecast Ultra from the other site. Has anyone been able to get something like that to work, or otherwise to get multicast over VPN working using some other method?

Someone recently did this with the UDMP/UXGP and has built a kernel with WireGuard. It is feasible that Cake could also be added this way. https://github.com/fabianishere/udm-kernel

I just published v4.1.37-edge2 which includes support for CAKE QoS as well as IP-VLAN, VXLAN and MAC-VLAN tap driver support.