Remotely discover new phones

[vanilla87]

We've setup 5 sites that all have VPN links between each other and the internet. At our main site we have our 3CX PBX server (Raspberry Pi). Currently if someone puts a new phone at another location, we do not "discover" the new phone. Based on my tcpdump, it looks like a multicast packet is used. As we use opnsense for our router, we tried to setup igmpproxy. However due to a lack of documentation and experience, we were never able to get it to work.

What is the best way to deal with this? I was hoping for a solution where any site can plug in a new phone and things will "just discover" but that is currently seeming less likely. I know I could pre-configure all phones at the main site, then send them off, but one or two people are out of state, so that's not trivial to deal with if/when that happens.

Thanks.

 

[SteveITS]

Are all locations in the same subnet?

Normally the solution for a remote location is to install an SBC at each location, in which case the phones do just appear in 3CX.

 

[vanilla87]

They are not. Each has a separate subnet.

 

[SteveITS]

Although it may be various VPNs and not "cloud" hosted I think an SBC would be the way to go here. It can be a Pi, if you can find one, or a VM or hardware PC. I'd suggest Debian as you basically just install it and point it to the 3CX server. A new phone will show in 3CX and you can assign it to its extension.

https://www.3cx.com/docs/3cx-tunnel-session-border-controller/
How does the 3CX SBC help?
The 3CX SBC overcomes common firewall issues and avoids unnecessary traffic back and forth to the cloud. Internal calls between phones located on the same network will be set-up directly with each other, without going via the internet link, resulting in improved voice quality.

 

[vanilla87]

Thank you for your assistance!