Working iax config using nat firewall
From MyWiki
[general] autokill=yes register => foo2:<password>@oooo.ttt.tk [bar2] type=friend secret=<same password as above> auth=plaintext host=<same as above> context=fromiax trunk=yes qualify=yes
Cloud instance [general] autokill=yes [foo2] type=friend secret=<same pasword as above> auth=plaintext context=twig trunk=yes qualify=yes