[plug] Mail without /etc/passwd

[Jeff Williams]

Is it possible to set up a mail server where all the authetication and 
user lookup is done on another machine? For example, I have a machine 
for authentication with a mysql database with users authentication 
details. Can I set up a mail server which will do SMTP, POP3 and IMAP 
for any user listed in the database? I want to be able to add, remove, 
lock users without editing any files on the mail server.

I know I can do authentication with pam, but I thought most SMTP servers 
check for a valid user on the system, or an alias.

Any help appriciated.

Jeff