I am trying to setup Postfix a few different domains on a virtual host.
I need to have email setup just to send out registration confirmations and new password requests. No one will have a mailbox on this server.
It seems this means that I want to setup Postfix as SMTP only.
I've also read about configuring Postfix null clients for simular needs.
What is the difference between Postfix null client and SMTP only?
Best Answer
Postfix Null clients means there are no local clients that it delivers email for. So you can still send email over it, but email is never going to traverse its way back to you via that server.
An SMTP only server can also be a null client server. Since SMTP is only for outgoing email a user could never pick the email up via POP/IMAP etc. But this machine could still be responsible for the email, so it is in my mind not always a null client server. For example email could be passed from here to an exchange server. So in that use case, the SMTP Only server is not just a null client server.