UDP bridge will not work unless you call 2 times

[jbraun]

We are having an issues with one of your udp bridges between two or our 3cx systems. the other 2 tunnels out of both end points work great, and all tunnels are set up the same way. Is this something that has been seen before as an issue with tunnel set up or do we have a network setting wrong, We have looked at both several times and can't find any reason why it would not work.

 

[Kevin Attard Compagno]

Hi there

This is not something we have seen before.

It seems likely that you may have NAT issues of some sort. Please be aware that Port Forwarding needs to be for UDP & TCP towards the Master PBX.

 

[jbraun]

I have fixed the previous issues, but we are now getting now audio on the problem bridge. The call goes through right away but no audio from either side is delivered. I have looked in the event logs and can not find any errors or abnormalities. Any advice?

 

[Kevin Attard Compagno]

Hi there

For a quick fix, try making a test call from Ext.A on PBX.1 to Ext.B on PBX.2 such that Ext.A and Ext.B are both set with the following parameters:

PBX Delivers Audio: ENABLED
Supports ReINVITEs: DISABLED
Supports Replaces: DISABLED

 

[jbraun]

Does that also need to be set on the bridge itself or only on the ext's

 

[Kevin Attard Compagno]

I would start by doing it on extensions AND bridge.

 

[jbraun]

Wanted to give an update on this issue. After fighting to get the UDP bridge to work to no avail, I switched the bridge to a TCP Tunnel and have had no issues since. The calls are clear and come through the first time every time

 

[Kevin Attard Compagno]

@jbraun

This almost certainly confirms my initial comment that it is a NAT related issue.