One of the problems with our old central mail system is that it was a black-box mailer configuration ; the valid localaddresses and domains were defined by what the mailer accepted, and whatthe mailer accepted was more or less in code, not in handy configurationfiles. This presented an obvious problem for the evolution of our mailsystem .

So our first job was to reverse engineer what addresses the centralmailer accepted, and figure out how to turn these into reusableinformation for the new mail machines we wanted tobuild