Solved Multiple SBCs connecting to one PBX?

[GrahamCM]

I am setting up for a client using a hosted instance of 3CX (ESXi not PBX Express) with 4 remote sites connecting via SBC.

PBX is current version (SR3) and has a public IP (no NAT).
SBC is version 15.5.7467 running on Debian 9.

Each SBC config is the default as created by the install and is working (in isolation) with all calls/blf/etc working.

The problem is that as soon as I connect a second SBC to the PBX, all extensions fail via SBC fail.

In testing I have SBC1 setup with two phones connected and working. Within several minutes of starting SBC2 (with or without phones connected), phones on both SBCs fail with "No Service" fail. At that point, stopping either SBC sees the other recover.

I have tested this against several PBX instances all with the same result.

Can anyone confirm current use with more than a single SBC connecting?
Can anyone offer suggestion relating specifically to using multiple SBCs?

 

[GrahamCM]

The PBXs are hosted in our data center. The SBC are at remote sites. Not a dumb question but all addressing is correct.

 

[GrahamCM]

This issue is resolved. Known issue.

 

[Saqqara]

To help others, what was the fix

 

[GrahamCM]

3CX chose to respond directly and in private. While I disagree with this approach, I'm sure they have their reasons. As such, I will not provide the details here.

 

[YiannisH_3CX]

Hello,

This is a known issue that has been addressed in the next SBC release. For those that might face the issue and cannot wait until the next SBC release please send me a private message and i will send you a workaround to deal with the issue.If the workaround does not work for you then you will have to wait for the next SBC release.
As this is a workaround we do not want to have publicly in the forums for future users to find because as i have mentioned this will be addressed in the next release.