[TriLUG] sendmail 8.11.6 virtual Host

[Jon Carnes]

On Fri, 2003-10-03 at 08:59, Jim Ray wrote:
> > 
> > Sendmail is an smtp server which means that it shuffles mail from one
> > place to another. If you want to download Mail, then you will need an
> > Imap or a POP server running as well. 
> > 
> 
> that's the part i don't understand.  so, something like exchange or wtf it is called now has both servers built into the same thingie.

Yes. Exchange has multiple services running, one service moves mail from
Point A to Point B (the smtp part), other parts allow a user to download
or look at the Mail (services running MAPI, IMAP, or POP3).

> 
> with sendmail, do clients have a choice of using pop3, imap and/or web to access the same blob wherefor sendmail doth spew?
> 
In Unix/Linux/BSD generally you run one smtp daemon (moves the mail
around from server to server), a local delivery agent (to move the mail
out of smtp and into a users local mail spool), and then any number of
other daemons that allow the user to download/look_at the mail in their
spool.

There are some applications similar to exchange in Unix.  At least
similar in that they act as all three parts: smtp, local delivery to
spool, remote access to spool. Cyrus is an example of just such a
creature:
  http://asg.web.cmu.edu/cyrus/

The Red Hat default for a mailserver is:
  - Sendmail (or Postfix) as the MTA, or smtp server
  - Procmail as the local delivery agent
  - UW-IMAP for POP or IMAP access to your local mail

Note that Procmail is not run as a daemon.  Instead it is called by
Sendmail. When Sendmail decides that an email should be delivered to a
local user, it runs Procmail and allows Procmail to handle the actual
delivery of the email into the users spool.

Procmail allows the sysadmin or the users to preprocess their incoming
mail using some simple rule-sets.

This also allows MTA's like Sendmail and Postfix to concentrate on doing
what they do best: shuffle email across the internet.

Hope that is helpful!

Jon Carnes