Re: [exim] Exim Clarification

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Author: Toralf Lund
Date:  
To: Exim Mailing List
Subject: Re: [exim] Exim Clarification
Telly Williams wrote:
> Hi,
>
>     I've recently started reading on Exim (particularly the Philip Hazel 2001 edition of his book) and I'm just getting a grasp on MUA's, MTA's, MDA's, etc.  

>
>     My question relates to the purpose(s) of Exim and Procmail.  From what I've gathered, Procmail handles delivery into your mailbox (or mailboxes) while 
> Exim is used for sending email (Transfer).  From what I've read about Exim, though, incoming mail to the server can be delivered to whatever folder/mailbox you 
> want it to go to through the use of Regex, Expansion, and the routers/directors configuration.

>

Correct. It is therefore not quite right to say "procmail handles
delivery while exim is used for sending email (Transfer)". A more
correct version would be "procmail handles mail delivery while exim can
be used for sending email *and for delivery*." In other words, Exim is
not just an MTA, but also an MDA - a mail delivery agent. (While
procmail is an MDA, but not an MTA.)

>     Assuming what I wrote in the 2nd paragraph shows at least a little bit of an understanding of Exim (and its MTA role), why is Procmail even needed?  It 
> seems like I only need an MUA, MTA, and Fetchmail.  Am I on the right path here?

>

More or less, but as someone else pointed out, you probably don't need
fetchmail. You want an MTA and MDA for transfer and delivery, and Exim
is both along with your MUA. And possibly something that helps the MUA
retrieve messages from where they are delivered, i.e. something like a
POP3 or IMAP server. Fetchmail is also concerned with this transfer, but
it's not the server part, but rather the message retrieval part of your
MUA implemented as a separate application, I believe.

- Toralf