Remote provisioning w/ SBC

[NickD_3CX]

It then grabs the config and provisions the phone for the extension but then it replaces the auto provision url with the local link instead of the public link.

I just tried this and gets the Public FQDN. Are you using default templates? Are you sure that during the installation process you entered the correct Public FQDN?
Also is the "System Status" node in the Management Console, under step #5, do you see the correct External FQDN?

Second problem is that it pushes the SCB PRIVATE address to both the SIP and outbound proxy address but the SIP should be the PRIVATE address of the 3CX instance.

For the 3CX SBC that is how it should be.

 

[NickD_3CX]

2. Per the setup instructions the SIP server address is supposed to be the PRIVATE address of the 3CX instance.
http://www.3cx.com/blog/voip-howto/conf ... extension/

This is an old article and this was for the 3CX SIP Proxy Manager, so I don't know how this mix up happened and it got updated but it is wrong, I will get it sorted out though so thanks for pointing it out. The correct guide is this one:
http://www.3cx.com/blog/docs/provisioning-a-remote-extension/

1. Yes, I show the proper FQDN on the system status.

If it is correct in the Management Console but the phone is picking it up incorrectly, if you can, open a ticket with the 3CX Support Team to have a closer look at this. I can't think what could be causing this.

 

[NickD_3CX]

Although it is usually not necessary but do the following:
- Stop the SBC service.
- Edit the SBC config file located in C:\ProgramData\3CXSBC\3cxsbc.conf (run notepad as admin, the go to the file).
- Remove the # from the following 2 lines:
LocalSipPort=5060
LocalSipAddr=0.0.0.0
- Leave the value or 'LocalSipPort' set to 5060, but for variable 'LocalSipAddr' set the value to the Local IP of the SBC machine.
- Save the file and restart the SBC service.

Also disable all unused Network Cards on the SBC and make sure that the priority of the active NIC is at the top of the list in Windows.