Can't forward call without using announcement

[stanhamil (Alan)]

I have a weird glitch with my FreePBX setup (16.0.40.7).

As part of my setup, I have an external number that is called and it simply routes the call out to a specific number via a different trunk using Miscellaneous Destinations with a different CID. It’s a simple call forwarding system.

However, I’ve found that unless an announcement is played before the outbound call is dialled, the caller only hears silence when the outbound call is dialled and has no idea that the call has correctly been connected.

To work around this for now, I’ve set a System Recording/Announcement which is 0.01 seconds of silence prior to the outbound call being made.

Any idea what could be causing this and how I can avoid the need to add an announcement before the outbound call?

Every other aspect of my setup works and I can dial out successfully using various trunks/CIDs.

[lgaetz (Lorne Gaetz)]

This is a symptom of a system behind a NAT router where the media port range is not being explicitly forwarded

SIP Port Forwarding

The nuts and bolts of SIP are complicated, but put simply: SIP session negotiation takes place over the signalling port (default 5060) and the audio (more correctly, the ‘media’) goes over a random pair of ports in the RTP port range (default 10k-20k). It’s quite common for providers to do SIP signalling and SIP media from different hosts, and some providers have many media servers. So imagine what happens when a SIP session is negotiated through a NAT router, but the audio appears from a differ…

[stanhamil (Alan)]

Thanks for your reply.

What is the difference when an announcement is placed before the outbound call and why is it that all other manually-dialled outbound calls work perfectly?

I’ve never forwarded any ports on my router, so do I need to forward any ports other than 5060 to my FreePBX installation?

[lgaetz (Lorne Gaetz)]

Answers to those questions are in the linked post.

[stanhamil (Alan)]

Ok, thanks.

Interestingly, my SIP provider has a “security” feature which limits connections to a specific IP address. This is currently set to accept connections from my IP address only.

If I disable this feature, is it possible this could resolve the issue? The connections to my trunks are made via username/password combination.

[lgaetz (Lorne Gaetz)]

If your system is behind a NAT router, and if the misconfig is with the NAT router, I don’t see how making changes at the provider will make a difference.

[stanhamil (Alan)]

Yes, that didn’t work.

As per the post you referred to, my RTP ports start at 10,000 and end at 20,000. Obviously, I could open up that entire port range to my FreePBX installation but would it be wise to narrow the port openings before forwarding those to my FreePBX installation? The installation is only for personal use and receives vey few calls.