I am in a weird situation that involves a sip trunk.
The normal use for dNAT is to translate a “WAN” IP/port to a Local IP/port and for a sNAT to translate a Local IP/port to a WAN IP/port.
I know also how to choose a different routes to the same server based on the source ip by way of mangle rules to mark the connection based on the IP address list and then route according to that mark.
But the situation I am into is beyond my expertise.
My PBX need to use several SIP Trunks, but the provider only accept traffic according to the source IP and do not use or allow a user/password way of registering. it is depending on the source IP to whom they charge the calls and not a user as we are use to.
So, in order to use both trunks I need to find a way for my PBX to connect twice to their server (lets say ip 200.72.224.30) and show a different source ip for each connection.
I was thinking about a NAT on reverse, so if I define a SIP trunk as IP 1.1.1.1, add an ip address (virtual nic) as IP 1.1.1.2 on the PBX then add the ip 1.1.1.1 on the router some how i should be able to translate all communications from 1.1.1.2 going to 1.1.1.1 to send to 200.27.224.30 as if that last ip was a local address and my pbx local ip was the wan side.
Any ideas?
Thanks a lot. I will attach an image of how things are configured so maybe someone can help me out.