I've not looked into either sendmail or postfix for large numbers of users, so I can't answer that for you. However, I am quite sure that pop3/smtp can be achieved in Postfix via "virtual accounts".

I've been having the strangest problem with my mail server running a combo of dovecot and postfix on FC6.<BR><BR>All mail seems to land and deliver fine at my server for the domains it's supposed to ...

Please note that this book is based on is based on Postfix 2.1, later versions of Postfix have new daemons not discussed in the book. This chapter describes how ...