Hi,
 
customers PBX----trunk-----kamailio------------freeswitch-------------carrier
 
We already add Trusted IP’s via SIREMIS 4.0
 
is it possible with Kamailio to have customers calls come in on a trusted IP and when they send calls we add a header with a [client id] which we can remove on the next ip switch upstream
 
So example
 
Call comes in from customer with IP:
their trusted IP source xx.xx.xx.xx
add header with their client ID

route to PSTN

Then my upstream switch will process the customers call and remove the header before sending to our voip carrier. Basically my ip switch will evaluate the client id header for billing, process and strip the header back out.
 
Thanks

Tony