I adore the name Aurelia , it ' s stunning . <| sep |> I ' ve watched every amazing and horrible second of this team this season . Including tonightBut tonight was the first time I actually wanted to just shut it off <| sep |> Out of the box , PJSIP has three ways to identify endpoints 1 By the user portion of the URI in the From header 2 By IP address as you ' ve done above 3 By mapping the request to the special ' anonymous ' endpoint which is the last resort , and only works if you ' ve defined the anonymous endpointIf you can ' t use the From user in your example , that would be ' 201 ' either because you can ' t know a priori what the users are going to be or because you don ' t want to define them all then you ' re down to IP address . If , however , you have two UAs sending you requests from the same IP address , then you ' re down to the anonymous endpoint , which isn ' t probably what you want . There ' s a few approaches you could take 1 Match based on From user , and create endpoints for the users that will send you calls . 2 Match based on IP address , but map all of your allowed Asterisk servers to a single endpoint . All calls would then be dispatched to a single context . Within that context , you can then perform more selective routing by examining information in the inbound INVITE request via PJSIPHEADER . 3 Since the PJSIP stack in Asterisk is pluggable , you could write your own inbound request identifier . This could then identify inbound requests and map them to endpoints using whatever criteria you ' d like such as a custom header .