I would like to suggest placing warnings to users of not just Engarde but any other Linux distro, that want to use the mail funcion, warning them that:-
"Unless one purchases a static IP address, it is now impossible to use any type of mail server to send out mail via WAN, mainly because domains are now refusing mail sent by dynamic IP's (either using highspeed cable, or DSL), Yahoo, Gmail, MSN, and Hotmail to name but a few refuse ALL mails sent by dynamic IP's, unless one pays for an external relay service."