What is Sendmail?

Sendmail is an open source mail transfer agent (or MTA) which is responsible for the routing and delivery of email. Sendmail is a remarkably flexible program, supporting many kinds of mail transfer and delivery including the overwhelmingly popular SMTP, which is what we use here in SCS.

For a bricks-and-mortar analogy, you can think of Sendmail as the software equivalent to the staff at your local post office; sorting mail, working to route messages with bad addresses, and generaly managing the behind-the-scenes business of delivering the mail.