SBC not connecting from specific location following update to v20

[BenchmarkFS-IT]

We are having an issue with one specific office where SBCs will no longer connect to the PBX. When plugged in at our primary office, the SBC is able to reach the PBX without issue.

As a side note, the PBX is hosted from Azure and is connected with a site-to-site VPN. All of our offices are interconnected that way and this is one of 26 offices that have this issue with SBCs, all others work. 3 SBC devices have been tried in this office, all are confirmed to reach the system in our HQ and other offices, but not this particular one.

 

[SteveITS]

FWIW I had a client with a problem at one of the owners' homes where a router phone would not connect, set its time via NTP, etc. but all other devices were fine. Long story short, ISP changed the ISP router and it works now.

 

[NicholasP_3CX]

If a site is connected via VPN to the PBX network, then you shouldnt need to use an SBC. Just provision them as local devices.

 

[noord]

If a site is connected via VPN to the PBX network, then you shouldnt need to use an SBC. Just provision them as local devices.

I also have this setup and I also do use an SBC.
I am under the impression, that when using an SBC, the local calls stay local - improving speed and latency because they don't need to travel over the internet (through the VPN).
Also, when the VPN fails, the SBC will still be connected to the PBX (PBX in the cloud) so the phones will still work.


I agree with Steve: it sounds like a router problem. I have had the same issue as Steve ( one device will not connected) at several sites during my career. However, the fact that you have tried 3 SBC's seems a bit strange.
Is the SBC connecting to the internal (VPN) IP address of the PBX?
Eg. I mean, is the SBC connecting to 91.192.256.3 or is it connecting to 192.168.256.5?

 

[NicholasP_3CX]

I also have this setup and I also do use an SBC.
I am under the impression, that when using an SBC, the local calls stay local - improving speed and latency because they don't need to travel over the internet (through the VPN).
Also, when the VPN fails, the SBC will still be connected to the PBX (PBX in the cloud) so the phones will still work.


I agree with Steve: it sounds like a router problem. I have had the same issue as Steve ( one device will not connected) at several sites during my career. However, the fact that you have tried 3 SBC's seems a bit strange.
Is the SBC connecting to the internal (VPN) IP address of the PBX?
Eg. I mean, is the SBC connecting to 91.192.256.3 or is it connecting to 192.168.256.5?

The audio will not go over the VPN or internet and stay local if you do not have recordings or PBX delivers Audio enabled.

You do need to factor in that you already have encryption and consequently, overheads, on your network and you are just adding to those with the SBC encryption as well. Just something to keep in mind.

 

[BenchmarkFS-IT]

The office's public IP somehow got blocked by the system.

 

[SteveITS]

Ah there it is, sometimes it's the easy things.