sendmail

sendmail

(messaging)The BSD Unix Message Transfer Agent supportingmail transport via TCP/IP using SMTP. Sendmail isnormally invoked in the background via a Mail User Agentsuch as the mail command.

Sendmail was written by Eric Allman at the University of California at Berkeley during the late 1970s. He now has hisown company, Sendmail Inc.

Sendmail was one of the first programs to route messagesbetween networks and today is still the dominant e-mailtransfer software. It thrived despite the awkward ARPAnettransition between NCP to TCP protocols in the early 1980sand the adoption of the new SMTP Simple Mail TransportProtocol, all of which made the business of mail routing acomplex challenge of backward and forward compatibility forseveral years. There are now over one million copies ofSendmail installed, representing over 75% of all Internet mailservers.

Simultaneously with the announcement of the company inNovember 1997, Sendmail 8.9 was launched, featuring new toolsdesigned to limit junk e-mail. SendMail 8.9 is stilldistributed as source code with the rights to modify anddistribute.

Latest version: 8.9.1, as of 1998-08-25.

The command

sendmail -bv ADDRESS

can be used to learn what the local mail system thinks ofADDRESS. You can also talk to the Sendmail daemon on aremote host FOO with the command

telnet FOO 25

sendmail

An SMTP-based message transfer agent (MTA) that runs under Unix. Developed at the University of California at Berkeley by Eric Allman in 1981, sendmail stores and forwards more mail than any other MTA on the Internet. In 1998, Allman commercialized the product by forming Sendmail, Inc. (www.sendmail.com), which offers a GUI interface for modifying the configuration file instead of dealing directly with more than a thousand lines of text. Sendmail, Inc. also offers a Windows version that includes the POP mail server and message store. Examples of mail clients developed for sendmail in the Unix world are elm, pine, mush and mailx. For information on the open source version, visit www.sendmail.org. See messaging system, BSD Unix and qmail.

Enterprise Mail System
This is a typical architecture of a large enterprise mail system. (Illustration assistance courtesy of Sendmail, Inc.)