Outbound bug and workaround in 3CX 18.0.7.441

[Boris.Minakov.ITNow]

Dear Support,
We have found a bug and also a workaround, so decided to post this. Maybe someone will face the same problem.

For example, in 3CX you have 2 Trunks:

1) Trunk_1 with number 1111, sip host: aaa.com, username: 11115
2) Trunk_2 with number 2222, sip host: aaa.com, username: 22225

But trunk username is different from numbers as displayed (both trunks are from the same ISP SIP Provider)

Create 1 outbound rule:
Rule_1 --> all calls for default group --> from Route_1 Trunk_1 with number 1111

Note: Trunk_2 is not defined in outbound calls

Now when you will call outside, 3CX will randomly choose caller id as --> 1111 or 2222
No matter if you have defined in outbound rule also -- > "Outbound Caller ID" as 1111

It will still randomly make calls from both numbers.


Idea and workaround:
We suppose that, as both numbers are from the same provider, they are treated as multiple DID (maybe), how ever these are 2 completely separated Trunks.
Or maybe, because DID and username does not match 3CX does not send correct information to SIP Server

Or maybe, depends on 3CX keep alive settings, who first (trunk) sends re-register keep alive request is treated as caller ID

Fix and workaroud:
For each trunk open trunk settings, go to "Outbound Parameters"

Change:
From : User Part (default is --> outbound caller id is taken from extension settings in manager console)
to
Custom

and put there each trunk username (for this current example 11115)

After problem will be solved and it will call with settings defined in "Outbound routes" and no random calls will be done

 

[TheodorosG_3CX]

Are you using a 3CX Supported provider?

 

[Boris.Minakov.ITNow]

Hello, its Generic Sip Provider.

As 3CX is SIP protocol based, honestly "3CX Supported provider" it's just a marketing, nothing technical. (SIP is worldwide standard)
Issue and workaround we described, we faced in multiple installations and decided to describe.

Currently, also it's not as issue, if proper troubleshoot... and change of outbound parameters settings, but anyway decided to write

Such issue, is faced when 3CX is connected to a SIP provider with Asterisk SIP Server as a core (Asterisk 13 currently)

 

[TheodorosG_3CX]

Allow me to disagree with the comment "honestly "3CX Supported provider" it's just a marketing, nothing technical"
The Sip protocol is one and common, but the way sip responses are handled varies between the providers as this depends on their infrastructure. 3CX has a dedicated Interop team who is responsible to perform all the interop tests with the provider to ensure for the normal functionality with the 3CX PBX Phone System and the provider. After all tests then this provider is supported and verified.
Using an unsupported provider you should always be aware that you might have several issues.
You mentioned though that you have changed a specific outbound parameter and is working, so i don't think this is a 3CX problem.