Terminology

Simple Mail Transfer Protocol

A protocol for sending e-mail messages between servers. Also commonly reffered as SMTP.

Fully Qualified Domain Name

The full domain name that includes all higher level domain names.

Domain Name Service

An Internet service that translates domain names into IP Addresses. Commonly referred to as DNS.

Spam

Unwanted illegitimate bulk mail.

Mail Relay

A server that routes an email to the correct destination. Mail relays are used to forward all mail for the local domain to the mail store.

Domain

A domain name is a name given to a group of machines. A domain name identifes one or more IP addresses. In an email address, the part to the right of '@' is the domain name.

Virtual Domain

A domain that exists as a software entity on the server, which doesn't need a dedicated hardware location. A server can receive mail for a virtual domain.