[OpenSIPS-Users] registrant example

[Alexey]

Hi all,

I would also like to mention the correlation between OpenSIPS configuration
parameters and SIP headers in the SIP-registration process:

according to the SIP protocol implementation, you are able to form the
username in the Contact: header of your outgoing REGISTER-requests.
In OpenSIPS you have to fill it in the 'binding_uri' column of the
'registrant' table [1].

E.g. you want the remote server to send you INVITE with 'alice' in the
username of the SIP Request's URI (rU [2] ), and your server's IP is 1.2.3.4,
so you have to add 'sip:alice at 1.2.3.4' into this column.

During outbound registration, your OpenSIPS will form the Contact: header
in it's REGISTER request smth like:

    Contact: <sip:alice at 1.2.3.4>;expires=3600

So, after successful registration the remote server will send INVITEs to your
OpenSIPS like:

    INVITE sip:alice at 1.2.3.4:5060;user=phone SIP/2.0

After that you can catch such rU using different techniques, starting
from simple hard coding in the script:

    if ( $rU == "alice" )
        xlof(L_INFO, "[$ci] relaying to Asterisk PBX");
        t_relay(, "192.168.88.11:5060");

... or in case if there are many incoming extensions, you may also use
Dynamic Routing [3] module, to detect how to route inbound calls, according
to prefix, filling the 'prefix' column of 'dr_rules' table [4] with
the same username,
you populate the Contact: header in outbound REGISTER-requests
and respectively the same which will send the remote server in its INVITEs.


[1] https://www.opensips.org/Documentation/Install-DBSchema-3-5#GEN-DB-REGISTRANT
[2] https://www.opensips.org/Documentation/Script-CoreVar-3-5#toc77
[3] https://opensips.org/docs/modules/3.5.x/drouting.html
[4] https://www.opensips.org/Documentation/Install-DBSchema-3-5#GEN-DB-DR-RULES


-- 
best regards, Alexey
https://alexeyka.zantsev.com/