Technical Tip: One way muting because of SDP getting translated

When one way muting is observed in Voice Call and observed in wireshark that the SDP port are getting translated or change after passing the FortiGate.

Create a VOIP Profile where no-sdp-fixup is enabled.

Then, apply this Profile in the Firewall Policy and make sure inspection is set to Proxy Inspection. 

When no-sdp-fixup is enabled, it turns off FortiGate's automatic modification of SDP information in SIP packets. Prevents the firewall from rewriting:

• The connection (c=) line in SDP.
• The media (m=) line in SDP.
• IP addresses and ports in the SDP payload.