We have a Sales office in middle east(Site-B) and a factory in a Asia country(Site-A). in both location we do have freepbx installed and SIP trunk connecting two sites.
At Site-B(middle east) we do have a SIP trunk from one ISP as our outgoing line and internal users can make calls and we don’t have any issues. even factory users(Site-A) can call sales users at Site-B by selecting the trunk, all are working fine.
The issue is: If someone from Site-A(factory) need to call a sales user’s mobile phone by selecting correct trunk and then outgoing line of middle east ISP sip trunk, call is failing.
Site-B ISP is rejecting the call. Reason is SIP Trunk Provider not allowing any calls from outside IP address. (in this case my trunk peer Site-A IP address).
Site-B ISP will not allow any remote IP as of security reasons and they want us to hide any remote/public IP address if we want to call via their SIP Trunk from external location.
Please be kind to give me any guide to resolve this issue.