Voip external server

[WLitdepartment]

I'm experiencing an issue with a connection to an external voip server.

Directly attached to a PA-500 ethernet port there is a patton (fxo voip appliance).

Now, I'm allowing any traffic to outside, any application.

When I surf from that interface I can access external sites, but the issue seems to be NAT.

Voip uses port 5060 udp.

I can see the packets reaching the external server (that I manage) and they are forwarded back, but on the PA they are not present.

I tried different NAT types, but none of them seems to be working properly.

Does anyone experienced the same issue?

Does anyone know how to solve the problem of udp coming back to the internal interface of the firewall?

Thanks to all of you,

Pietro

[dpalani]

Is the proxy server able to establish a sip session successfully with the external server ? Is the proxy server a nat aware device( does it know its public ip address ) ?

[shasnain]

have you tried a static bi-directional nat for this traffic.

[_slv_]

Please read this topichttps://live.paloaltonetworks.com/message/15066#15066

it could help you - try to use application override

regards

SLawek

[WLitdepartment]

The external server is well known by the patton.

It arrives and the landing packet reaches the target.

When the packet is sent back everything stops.

Now I'm trying the hint given by slv.