Does SMTP and IMAP servers each require separate passwords?

Question

I'm building MTA server. Also I use IMAP server to serve user's mail to that particular user.

Does MTA and IMAP server each require different passwords? I know that they are separate entities that perform disparate functions on processing mail.

Still, when I use my MUA it only asks me one password. Why doesn't it ask separate passwords for MTA and IMAP separately?

Answer 1

The SMTP and IMAP servers are separate as far as your mail client is concerned, and that's true for nearly all clients I've tried so far. (Well, some do have an option to "use the same credentials as IMAP", e.g. Outlook does.)

Although the two servers can share authentication information, and nearly always do. For example, both Postfix and Exim can be configured to use the Dovecot SASL provider. Alternatively, all three can use Cyrus SASL as the backend (which itself can use saslauthd, which can use PAM or whatever). And so on.

Of course, the mail app doesn't need your SMTP password until it actually tries to send a message, so it won't ask for that until then.