Intermittant one-way audio

Asterisk Asterisk Support
1

Hi there,

I’ve got an Asterisk system (10.4.0) setup that will randomly experience one-way audio. It doesn’t seem to happen with any consistency on a particular phone or service and when it happens while leaving a voicemail the message can’t be left (no audio from speaker error). It’s behind a static IP address forwarded from our router and there seems to be no obvious configuration issues. When it happens there are no obvious signs in either the Asterisk Console or in the /var/log/asterisk/messages log.

Any tips on troubleshooting this issue?

2

So if I am not mistaken, the Asterisk server is behind NAT? Do you have “localnet” and “externip” parameters set on your Asterisk box?

You will definitly need to make some more debugging on your part. The best thing would be to capture packets on the Asterisk server (tcpdump) and analyze them for the case when the one-way audio happens. With the current information you posted I would think that the problem is in your NAT router.

3

So I’m still seeing this issue. I was able to capture a tcpdump of a call where it had the one-way audio issue, what are some signs to look for? I’ve configured everything for NAT but still no luck. This happens to perhaps 1 call out of 10.

4

Check the SIP messages (To, From, Contact headers and SDP) for IP addresses (local/public).

You can also check if Asterisk receives the RTP stream from the remote speaker (that it’s not blocked on a NAT router).