Outbound call failing and repeating

Have run into an interesting problem. When one of my clients dials out, most of the time it hangs for a while, no audio coming through. On the receiving end, the phone will ring, then if you pick it up the call will end, then ring through again and this time it will work. Spoke to the Trunk provider and they say it’s our firewall, because they have a packet capture that shows “Destination unreachable (Port unreachable)” as they are sending "Status: 200 OK | " So basically we are sending the call request, they are sending the 200 OK, but the OK is not reaching us, it’s getting a port unreachable. After about 10 seconds of this the call ends and it initiates a second call, this one goes through without an error. Just says Trying, session progress, OK. I have double checked the firewall and there are no rules which would block messages from the trunk to asterisk. I even disabled geo-ip filtering and it made no difference. The path is completely open and still the message is getting blocked. If anyone has seen anything like this before, it would be amazing if you could tell me what you did to fix it. I have this feeling it has something to do with NAT, but unfortunately I’m not very familiar with NAT and I wouldn’t know where to start in terms of troubleshooting.

we have same problem auto redial

Turns out it was an RTP issue. Broadvox uses a hugely wide RTP range, which extends beyond the default 10000 to 20000 that FreePBX has. I disabled strict RTP enforcement and the problem stopped immediately. I feel like Broadvox should be aware of this by now…

Hi Matt,

I think I am having the same issue, how do you disable strict RTP enforcement?