How to raise your SIP server?

Question

Telephony

Hi everybody. I have a dedicated server. And two ios devices.
I want to raise SIP on the server and call from one device to another.
Where to dig? How is this set up correctly? how to add a client? How does the server understand that the call should be addressed to a specific client? I'll figure it out myself, I just can't figure out how it works.
Ios application makes a request to the sip server, and then how and what happens?
In addition, in the future you also want to add the ability to call landline and mobile numbers, what should be integrated with here?

Answer 1

1. Asterisk
2. FreeSWITCH
3. YATE
4. OpenSer My
preference is FreeSWITCH.
Only this fun will be enough for you for many months of work - these are all very complex products, each with its own "character".
This is obtained from a cannon on sparrows.