We have installed a PBX on AWS and connected it to our on-prem Router via VPN.
My on-prem router is connected to the SIP provider via a physical connection with another on-prem MUX device (device given by sip provider).
All connections are working fine, EXCEPT, my SIP provider has a condition that all connections to their server must originate from a specific IP that they have assigned to us.
Since AWS machine is connected via VPN, all calls from PBX are picking up the IP of the AWS machine as "source IP".
For resolving this, i need to replace / masquerade / NAT / change the IPs of all connections from AWS machine's IP to SIP provider's assigned IP. Someone suggested i need NAT loopback/reflection for this. Someone also suggested packet forwarding. someone suggest IP masquerading.
Please guide how can this be done?