SIP Trunk - Type of Authentication = Outbound - Outbound only broken

[Robert Nelson]

According to the documentation at https://www.3cx.com/docs/sip-trunk-registration-authentication/ :

“Outgoing Outbound Only”: 3CX does not send REGISTER messages, but is prepared to authenticate if an outgoing INVITE is challenged by the provider.

However that doesn't match the behaviour I'm seeing where it does in fact send register requests on outbound only SIP trunks.

 

[cobaltit]

Is this actually creating a problem or is this an educational exercise? If the former, does setting it to 'No authentication' allow things to work?

 

[drewt]

Any chance you are getting log entries that look like this?

Call or Registration to 40x3827648@(Ln.10001@XXXitelity) has failed.
xxx.2.142.109 replied: 480 Temporarily unavailable; from IP:xxx.2.142.109:5060

I have been seeing this in the last month randomly, relating to out bound calls. My ITSP gives it the official shrug but I have not heard complaints from any customers.

 

[YiannisH_3CX]

Hi,

These options have been deprecated and they basically act like the Register/Account based option. They will register and authenticate to the provider.
If you want the PBX to authenticate to the provider during outbound calls but not register you can use the "Do not require - IP Based" option. Given you also provider credentials to the trunk the PBX will respond to a challenge request from the provider.

 

[Robert Nelson]

Specifying Do not require - IP Based and then providing credentials causes 3cx to place the username in the INVITE URI. This causes the provider to reject it with a 404 Not found. It also seems to be contrary to the RFC which states that the INVITE URI should have the same URI as the To, the exception being REGISTER requests.

 

[YiannisH_3CX]

Specifying Do not require - IP Based and then providing credentials causes 3cx to place the username in the INVITE URI. This causes the provider to reject it with a 404 Not found. It also seems to be contrary to the RFC which states that the INVITE URI should have the same URI as the To, the exception being REGISTER requests.

Are you referring to outbound calls from the system? If so then make sure that in the outbound parameters of the trunk the field "Request Line URI : User Part " is set to "CalledNum" which is the default value set in the generic sip trunk template.

 

[Robert Nelson]

Never mind, the outbound URI was a change I'd made earlier trying to get it to work.

The issue now is that Vitelity returns 486 Busy Here instead of a 401 Unauthorized challenge.