Intermittent Audio

I am having a problem with our FreePBX system. Basically intermittently no audio is sent from the FreePBX system.

If I call our main number, sometimes our IVR will play, other times it will time out. Then if a call is connected, I am able to hear them but they are unable to hear me.

I am very puzzled by this because i’ve had this system running for about 6 months now and not a single problem. Then last week for an entire day it was doing this, then it stopped. I have made no changes to the network, firewall, IP’s or anything like that.

Now it has reared it’s ugly head again and it’s driving me crazy.

Any help will be greatly appreciated.

It is impossible to assist you if you do not provide more info. What version of FreePBX and Asterisk? What kind of trunks are you using?

Sorry, first time posting so I wasn’t sure what was needed.

We are using SIP trunks, Asterisk 11.7.0 & FreePBX 2.11

The audio for each call will be on pairs of ports as limited in your /etc/asterisk/rtp*.conf heirearchy

make sure you limit it to something reasonable, start and end on an even number and that your router has those ports equally covered, from asterisk cli you can

rtp set debug on|ip

to watch the flow of a broken call for clues.

Thanks for the tip, if it acts up again i will do that and see what it happening and report back.

Thanks again.

Sure enough it started to act up again this morning. Switched on RTP debug and discovered that the FreePBX system isn’t sending out RTP packets. It is getting them from my SIP provider, but won’t send them out which would explain the one-way audio.

However i’m still confused as you why it is an intermittent issue. If i do nothing and let it sit for maybe 30m to an hour it seems to correct itself. But because this is an in production system for our office phones, i can’t have that. Plus it is just irritating.

You will have to look at the SIP session from the beginning of the call and the SDP negotiated connection that ensues

sip set debug ip a.b.c.d

That’s what i was looking for, [had issues with the syntax earlier]. Once the issue rears it’s ugly head again i’ll give that a go and see what I find.

This issue went away for a while, about 2 weeks. Then all of a sudden it came back. However i have found the answer.

A firmware update for my firewall changed some of port settings and i didn’t realize it. Once those were figured out, we seem to be golden.

Hopefully it will stay that way.