Configuring Dynamic DNS!

If your server is already in the Internet don't care about it.
In my case, server is staying in my home. So I need to use Dynamic DNS Resolution Service. You have many choice of this service, i used DynDNS.org

First you need to register to this site and get those services.

Second configure your dynamic Domain Name on your rooter!



Third configure port forwarding on your rooter



After all you need to configure Dynamic DNS in your Asterisk using sip_nat.conf

Write inside the sip_nat.conf:

externhost=yourdomain.dyndns.org;
externrefresh = 5;

localnet=192.168.1.0/255.255.255.0;
nat=yes;

And of course restart Asterisk!

Read More about Dynamic DNS in Asterisk