Below I detail how to set up a basic asterisk dial plan with 2 extensions, a SIP Trunk provider, and incoming calls ringing both extensions. in /etc/asterisk/sip.conf add: [100] ; extension 100 username=100 secret=100 host=dynamic nat=yes type=friend qualify=yes context=phones [101] ; extension 101 username=101 secret=101 host=dynamic nat=yes type=friend qualify=yes context=phones [SIP-PROVIDER] ; Trunk to/from SIP Provider type=friend…