What is an open mail relay program?

An open mail relay is a mail server program that will accept emails sent from a third-party and forward these emails to different third-party computers, while bypassing your email program (i.e. Microsoft Outlook). This is done without your consent or knowledge. From the point of view of the recipient of such emails, open mail relays are a nuisance. Most email sent through an open relay may be considered to be spam.

After gaining access to your computer (through the use of a virus or Trojan program), a computer hacker is able to redirect and/or send large quantities of email through your computer. You may have allowed your computer to become an open mail relay by either downloading programs containing hidden malware (short for “malicious software”), or perhaps your computer has become infected with a virus. Either way, all spam sent through your open mail relay will appear to have originated from your Internet connection.

Development: WMAD.