what the tech meant was that if u have any firewall open
then make sure that the firewall does not retrict anyone
to enter ur mchine thru the door [ port ] named 50, 500 , and 51.
but if u dont have any firewall or software such as tcp wrapper than the chances are that this ports arent blocked in any way.
u cant open this ports ... they are opened by softwares and u need not worry except if u have firewall ..... so make sure ur firewall is not blocking connections on this ports.