Asterisk on RT-AC66U - no audio behind NAT

[StephanBolten]

Hi,

I am on the latest Merlin firmware

I successfully installed asterisk18 through entware on the AC66U. I have three SIP devices which I successfully configured: They can call each other without problems when @home. As soon as I am remote I can still successfully register with the asterisk service (using CSipSimple on all of my devices) I can call - it rings - I pickup and then: no audio in both directions.

I have started google'ing and found that I might have to do the following:

- open rtp port range in the firewall for udp (10000:20000) - put that one in the firewall-start script
- disable SIP passthrough in the NAT settings in asuswrt merlin

I have done both - restarted the router with no success - still no audio. I have no clue how I could solve the problem. Any hints very much appreciated.

/jffs/scripts/firewall-start
#!/bin/sh
iptables -I INPUT -p udp --destination-port 5060 -j ACCEPT
iptables -I INPUT -p udp --destination-port 10000:20000 -j ACCEPT

/opt/etc/asterisk/sip.conf
[general]
context=fromInternet
nat=yes
transport=udp
sipdebug=no
allowguest=no
alwaysauthreject=yes
bindaddr=0.0.0.0
externip=<myddnsURL>
localnet=192.168.0.0/255.255.255.0
qualify=yes

[1000]
permit=192.168.0.0/255.255.255.0
type=friend
context=phones
host=dynamic
secret=<password>


Stephan