Hi
You shouldn't need to do anything on the SAIL machine. SAIL will automatically open the necessary ports. If the SAIL server is behind another firewall then you should open and forward 5060 if you intend to use SIP or 4569 if you intend to use IAX2.
For SIP you may also have to open and forward 10000-20000 depending upon whether your carrier is running session border control.
Kind Regards
S