New user checking on SIP proxying use case - sr-users

22 Jul 2021

Hello all,

My name is Nick Hurlburt, and work with a nonprofit tech organization that provides a
software platform for child helplines around the world.  I am a new user to Kamailio, and
I'm interested in figuring out if my use case is appropriate, getting some tips on how
to go about it, and possibly enlisting some expert help.

Our service is built on top of Twilio, but we are working in some countries where Twilio
doesn't have phone numbers.  So in those areas, we are working with local telecoms on
ways to integrate using a SIP connection.  In one particular example, the telecom company
can send SIP INVITEs but can only address them to a static IP.  However, Twilio needs to
receive the invite addressed to a fully-qualified domain name (eg,
example-setup.sip.twilio.com).  The idea arose to use Kamailio as a proxy to accept the
static IP-addressed request and then rewrite the request to pass it along to a domain
name.  Then once the connection is established between the two endpoints, the media can
flow directly between them.

I have a software engineering background but still coming up to speed when it comes to
VoIP technology.  I'd be interested in:
- does this sound like a good use case for Kamailio?
- is there any specific documentation you could point me to for this use case?  (I have
been looking at the Kamailio documentation, but a quick pointer could save a lot of time
in digging through it)
- if anyone from the community would be open to helping us develop a
prototype/proof-of-concept instance of this, especially if you're open to contributing
to a nonprofit on a volunteer or discounted rate, I'd love to talk more

Thank you,
Nick