What would smartertools email product be considered? A MTA or MDA or both?

Question

I am not much of a sysadmin, but I did manage my own windows server (dedicated server rented from theplanet), using smartertools to manage email.

This allowed me to host my own domain's email, send and receive email.

This seemed to be a 360 degree solution in terms of email, what would a unix/linux based alternative be? (would it be a combination of products or a single solution?)

Just a little confused as to a MTA and MDA etc.

Answer 1

A full-blown Mail Transfer Agent are smart-hosts like sendmail and postfix and are very common. These are packages that send AND receive mail and support the related RFCs for handling mail. IIRC, the SMTP daemon in IIS is just barely smart enough to qualify, where the Exchange Edge and Hub Transport roles definitely do.

A Mail Delivery Agent is what delivers email from an MTA to the actual mailbbox. Not all mailing systems have them, and sometimes this is bundled invisibly inside the MTA software itself. The 'procmail' package is such an MDA, and in sendmail parlance they're called "milters'". Unfortunately, the definition of MDA is a subset of milter, as a full milter has the ability to affect mail flow both directions. The Windows equivalent would be the Exchange Mailbox role, and anything that can leverage the anti-virus hooks in the Edge/HubTransport/ClientAccess roles.

Answer 2

Have a look at the these two pages: MDA, and MTA. You can find the definition of each one. Also, you can find a list of software for Unix-like systems.

Answer 3

I'd definitely recommend both sendmail and postfix as good choices for MTAs (in preference to rmail, qmail, exim). IMHO, postfix is easier to configure, but I'd look at Sendmail for very high throughput applications.

If you're planning on implementing support for a large organisation (or a lot of sites) then you might want to have a look at running an LDAP system to route mail.

sysadmin1138's answer is a bit misleading - an MDA is NOT a milter, and a milter is NOT an MDA. A milter is policy tool for an MTA. Milters and the milter API were originally proposed and implemented by Sendmail - but IIRC are binary compatible with Postfix. Its a good idea to add in some security milters for incoming mail (spamassassin, anti-virus) and if your processing large volumes of messages, something like milter-limit to throttle output.

As for MDAs - there's lots to choose from. Procmail usually comes as standard on most Linux distro's these days and provides a huge amount of flexibility / configuration for routing messages, auto-responders, and out-of-office handling. Out of the box, this will write mail into mbox or maildir formats so they can be picked up and presented via a POP or IMAP server.

Which brings us neatly to the POP/IMAP server - the UoW one which comes bundled in most Linux distro's is OK for small workgroups, but for larger installations, you might want to have a look at Dovecot or Cyrus.