Issue in v20 with Remote Phone(s)

[TMC]

We are having issues with remote handsets losing registration in v20 - sporadically. Looking at Logs and performing extensive testing, it appears registration will fail even - where the use of site-to-site VPN and Split DNS should allow if the phone is manually set for provisioning - or even manually configured. If the handset that was failing registration is moved to the same LAN as provisioning - it completes and then can be used on the remote LAN.

In reading recent forum and blog posts, it appears that an SBC or an SBC-capable phone is now possibly required for each Location LAN - but don't understand why since the re-provisioned phones work on the remote LAN after re-provisioning. Can someone comment on this - this is a serious issue, since providing an always-on SBC or a new/changed handset and subject to another single-point-of-failure besides the PBX is NOT desirable?

 

[SteveITS]

v18 and prior allowed the "STUN" connection method for phones, though 3CX discouraged and didn't support it. In v20 that requires a custom template. Done properly a STUN setup requires ports forwarded to each phone.

Using an SBC eliminates all that because the phone creates a tunnel to the server. You can have more than one router phone per location (each phone). Phones added behind it can then be PnP.

You mention a VPN though, if it is passing the broadcast traffic and all on the same network that should be OK...? Can you browse to the 3CX server from the remote network?

 

[TMC]

v18 and prior allowed the "STUN" connection method for phones, though 3CX discouraged and didn't support it. In v20 that requires a custom template. Done properly a STUN setup requires ports forwarded to each phone.

Using an SBC eliminates all that because the phone creates a tunnel to the server. You can have more than one router phone per location (each phone). Phones added behind it can then be PnP.

You mention a VPN though, if it is passing the broadcast traffic and all on the same network that should be OK...? Can you browse to the 3CX server from the remote network?

Thanks for the reply Steve! Not on "same network" but site-to-site VPN should handle the routing without requiring NAT (inside the tunnel). Yes, can browse 3CX from the remote network - either by IP or by FQDN (split DNS resolves to LAN IP).