Asterisk: The Future of Telephony, 2nd Edition

Asterisk and VoIP

It should come as no surprise that Asterisk loves to talk VoIP. But in order to do so, Asterisk needs to know which function it is to perform: that of client, server, or both. One of the most complex and often confusing concepts in Asterisk is the naming scheme of inbound and outbound authentication.

Users and Peers and Friends—Oh My!

Connections that authenticate to us, or that we authenticate, are defined in the iax.conf and sip.conf files as users and peers. Connections that do both may be defined as friends. When determining which way the authentication is occurring, it is always important to view the direction of the channels from Asterisk’s viewpoint, as connections are being accepted and created by the Asterisk server.

Users

A connection defined as a user is any system/user/endpoint that we allow to connect to us. Keep in mind that a user definition does not provide a method with which to call that user; the user type is used simply to create a channel for incoming calls.^[117] A user definition will require a context name to be defined to indicate where the incoming authenticated call will enter the dialplan (in extensions.conf).

Peers

A connection defined as a peer type is an outgoing connection. Think of it this way: users place calls to us, while we place calls to our peers. Since peers do not place calls to us, a peer definition does not typically require the configuration of a context name. However, there is one exception: if calls that originate from your ...