[asterisk-users] Call bridged, but no sound

[Brian Candler]

On Thu, Oct 12, 2006 at 02:26:16PM +0200, Norbert Zawodsky wrote:
> As soon as the connection is up and the receiver is lifted on both
> sides, the leds of the DSL Modem between Asterisk and my ISP, and the
> leds of the switch between Asterisk and the SNOM phone start rapidly
> flashing. So I assume there are lots of data packets on the wire. But no
> sound in both receivers.... Could it still be a firewall problem?

tcpdump is your friend, and a lot more useful than a flashing light :-)

# tcpdump -i eth0 -n -s0 udp

Look at the source and destination IPs and port numbers of the packets.

You might see:
1. packets from phone to Asterisk
2. packets from Asterisk to phone
3. packets from Asterisk to outside IP address
4. no packets from outside world to Asterisk

Or you might see:
1. packets from phone to outside IP address
2. no packets from outside IP address to phone

The message "Attempting native bridge" makes me think of this second
possibility. If so, you could try setting nat=yes and/or canreinvite=no on
the channel to the SIP provider, so that Asterisk proxies the RTP data.

Regards,

Brian.