We use many electronic mail terms and acronyms throughout this book. In this section, we briefly cover some of the basic terminology that you’ll encounter.
Mail Transfer Agent (or Server)
A mail transfer agent (MTA) is a program that transmits messages from one machine to another. We use MTA interchangeably with “email server” throughout this book. Examples of MTAs include Sendmail, Postfix, qmail, MS Exchange, and Lotus Domino.
Mail Delivery Agent
A mail delivery agent (MDA) is a program that delivers messages to users’ mailboxes. Sendmail ships with the mail.local utility, which writes messages to users’ mailboxes. You can also use Procmail as an MDA. Some MDAs are incorporated directly into the MTA, such as Lotus Domino ...