When trying to connect an external sip client to my home Asterisk (Trixbox) after setting up the extension with nat=yes and qualify=yes I could connect and register to the machine, you can check this by using ‘sip show peers‘ from the asterisk CLI

To resolve this issue, I manually edited the sip_nat.conf file, below is my configuration.

nat=yes
externhost=XXXXXXX.dyndns.org
localnet=192.168.1.0/255.255.255.0
externrefresh=120

If you have a static ip, you can use externip=xxx.xxx.x.xx instead of externhost

Also, in my sip.conf file I have the following.

bindport=5060 ; UDP Port to bind to
bindaddr=0.0.0.0 ; (0.0.0.0 binds to all)
rtpstart=10000
rtpend=20000

You can edit these files via the config editor built into trixbox, or from an SSH terminal using Putty with the easy to use nano text editor

You may also need to point the following ports to your asterisk / trixbox from your router

SIP port: 5060
RTP Ports: 10000 – 20000

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