We have an IP phone system that we are trying to get up and running on our network.
We've created the VIP with forwarding from the phone systems external IP to our internal IP and opened the necessary ports as well.
We've added it to the firewall policy and have the phone and see and ring each other on the network, but the call will connect with no audio on both sides. We added the phone systems external IP as a secondary IP on our Wan1 interface. This gave use audio on internal office calls, but anything outside the LAN still has no audio.
Any ideas would be great. I'm not a networking person, but unfortunately, trying to fill the role.
The SIP session helper that is turned on by default on FortiGate often causes more problems than it solves. Where I am using interoffice SIP, I know I have it disabled and the same problem you are describing is one I initially had when getting it going. So try disabling the session helper.
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