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acvaldez
Staff
Staff

Created on ‎04-14-2025 12:43 AM

Article Id 387443

Technical Tip: One way muting because of SDP getting translated

Description This article describes a scenario in which it is possible to use no-sdp-fixup in VOIP Profile.
Scope FortiGate.
Solution

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.

 

sdp image 1.png

 

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

 

sdp image 2.png

 

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

 

sdp image 3.png

 

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.
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