Connecting to the world with gateways

The counterpart to having a user register to your FreeSWITCH server is to have your server register as a user on a remote server. This is accomplished using gateways. A gateway is quite simply a way to authenticate with another SIP server. This includes authentication challenges to SIP REGISTER attempts as well as INVITE messages. Telephone service providers use very large servers (including some running FreeSWITCH!) to provide SIP trunks to their subscribers. In FreeSWITCH, we can use a gateway to connect to a SIP provider. We can also use a gateway to connect to another SIP server, such as another FreeSWITCH server or any SIP-compliant IP-PBX.

Setting up a new gateway

A gateway simply connects to a SIP server just like a SIP phone connects to FreeSWITCH. As such, a gateway configuration bears some resemblance to a SIP phone configuration. Like a SIP phone registering to FreeSWITCH, a gateway has some minimum requirements. They are as follows:

• Username...