Inbound SIP Trunk settings

This is a general question on creating a SIP trunk and registration string. I’ve created a lot of SIP trunks using the Outgoing Settings - Peer Details and Incoming Settings - User Details but haven’t used the Registration String.

If you use the Registration String, do you still need the Incoming Settings - User Details?

The goal is to simulate a SIP VoIP service provider in my VoIP lab for the students to connect to. I would like them to register using the registration string.

The registration string is used in conjunction with host = dynamic so the peer can inform the server of it’s IP address.

Would this be in the Outgoing Settings - Peer details instead of the static IP address. This is making sense to me now. I’ve created SIP trunks between PBXs with static IP addresses. If it was an IP phone then I would use the registration string as the IP address would change. Correct?

Correct, The registration string is independent of the peers. FreePBX gives you two slots to create peers in a trunk (and confuse people). That is only required if you carrier had different outbound setting than inbound (or the other way around).