SIP register with X-Lite

To complete my understanding of connecting through SIP, help me tear this apart.

register => 102:102@fromdomain.com

The place, fromdomain.com, needs to be the domain/ip address of the computer hosting the X-Lite softphone, right?

For example, I have a domain set up to redirect all 5060 traffic to my PBX. When I am on the network, my softphone works great. It connects and can make outgoing and receive calls. However, when I am on another network, the softphone fails to work. This is without updating the register line.

In order for this to work, does * need to be aware of the IP/domain that my softphone is on?

This will work if you are setting up a highly restrictive environment. Such that you want to preclude the possibility of any stations from other IP addresses or domains connecting to your Asterisk server.

You can also setup your SIP environment to be dynamic, so that the IP address isn’t fixed.

Click here for more details… http://www.voip-info.org/wiki-Asterisk+config+sip.conf