Dovecot versus Postfix

[Rashkae]

Jan Sneep wrote:
>>From the Gnome desktop, under System -> Administration -> Services I can see
> that both Dovecot and Postfix are up and running and both are shown as a
> "Mail Agent".
> 
> What's the difference between the two? Do I need to have both running on the
> server or is just one sufficient?
> 
> I have found pages at https://help.ubuntu.com/community for both. Dovecot is
> described as a "Mail Deliver Agent" and Postfix as a "Mail Transfer Agent".
> Does one rely on the other? Do I need to configure both?
> 
> I want to replace an old Windows mail server that came with Windows '95, and
> yes has been working beautifully without so much as a single hiccup over the
> past 12 years. It is used just to transfer mail to other users on the LAN,
> actually just between my wife and I. Two mailboxes and we use it 90% of the
> time just to send each other calendar appointments, so we know what plans
> the other has made. The rest of our mail we send directly to our ISP's mail
> server for delivery and we grab our incoming emails directly from the three
> ISP mail servers that we have account on.
>
> 
> Can anyone help with these questions?
> 

You *probably* just want Postfix for local mail delivery, and not bother 
with Dovecot.

Postfix is used for sending e-mail, and for the local computer to 
receive e-mail. (example, if you have two user accounts, and you want to 
send e-mail from one to the other, postfix would be the glue that does 
it.)  Since you'll likely be using ISP smtp server for sending e-mail 
externally, you are only likely to use postfix for the example of 
sending mail locally to your wife's user account.  This is assuming you 
are using something like Evolution as your mail client, which is able to 
receive e-mail directly from the unix standard mail spool.

Dovecot is the server used by users to retrieve their e-mail from a mail 
server to their local computer or e-mail program.. for example, if you 
open outlook and check mail from your ISP, dovecot (or a similar 
program) is what would be used from the ISP side.  To make life 
interesting, if you are using a mail client that doensn't use or 
retrieve e-mail from the standard unix spool (like Thunderbird, which is 
what I use) and you are sending e-mail internally to user accounts on 
your computer, you'll need to install dovecot so the e-mail client can 
retrieve those locally delivered messages.

The good news is that neither postfix nor dovecot need any configuration 
for strictly internal usage.  Simply installing the packages should suffice.