# Questions abouit Diff mail servers

## d4mo

Let me know if I have this right.

Sendmail, Postfix and Courier are all MTAs.  And MTA handles the transfering of emails between servers or from client to server.  To get mail to the client you need an IMAP or POP3 server that gets the emails from the MTA.  Then the client gets the email from the IMAP or POP3 server.

Is that correct?

Question 2.  If the above is correct, why use Postfix + Courier or Sendmail + Courier?  When from what I've read Courier has built in IMAP/POP3 functions so you should just be able to use Postfix on it's own.....correct?

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## Anarcho

Your are correct:

MTA - Mail transfer agent - handles SMTP traffic

MDA - Mail delivery agent - handles storing of mails in the mailboxes of the users and delivery to their MUAs e.g. POP3, IMAP

MUA - Mail user agent - is your email client, e.g. thunderbird

But postfix is "only" a MTA and doesn't include POP3 and IMAP. It only delivers to a local folder (which was OK in the first days of the internet).

And AFAIK postfix is much more powerfull than Courier in its MTA possibilites, so thats why you usually combine postfix with courier to have SMTP and POP3/IMAP.

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