VoIP over NAT issues: Ring but no audio; disconnects

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VoIP over NAT issues: Ring but no audio; disconnects

L1 Bithead

I have our VoIP PBX set up with an IP on our external side via NAT. The policy is a simple static NAT from the internal IP to the external. I also have the correct security policies in place to allow SIP/RTP traffic to pass freely to and from the external IP address. The PBX server can be accessed via HTTP from outside our network, and my cell phone (using BRIA) can successfully register to the PBX.

However, whenever I make a call from outside, it will disconnect after seven (7) seconds when picked up. This happens every time without fail. I have tried tweaking around security policies, enabling application override, and altering the NAT rules.. nothing seems to help.

Can anyone give me suggestions? This setup worked perfectly fine on our old Juniper SRX-240B with the PA-500 in vWire. Ever since I swapped the PA-500 into being our gateway/firewall, it just won't do it.

More information can be provided upon request.




Yesterday i have sesion with support from LA and waiting for solusion.


did u resolve problem


I had the same problem and finally pointed the outside interface of the VOIP PBX to the internet bypassing the PAN. It has a built in firewall that's satisfactory for it's purpose. I created a zone on the PAN to get to he voice subnet for secure management of the VOIP PBX and also to keep the voice subnet off my internel network. It works for now.

L1 Bithead

yes, my problem is resolved. support offered  in my case to use application ovverride for sip application, and it's work.

Not applicable


I'm experiencing the same problem.  Could you provide details of the application override fix please?

Mine looks like this, but is not working;


The 10. address is our PBX, the 80. address is the remote PBX and the 5. address is our external IP.

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