Also found in: Wikipedia.


The BSD Unix Message Transfer Agent supporting mail transport via TCP/IP using SMTP. Sendmail is normally invoked in the background via a Mail User Agent such as the mail command.

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

Sendmail was one of the first programs to route messages between networks and today is still the dominant e-mail transfer software. It thrived despite the awkward ARPAnet transition between NCP to TCP protocols in the early 1980s and the adoption of the new SMTP Simple Mail Transport Protocol, all of which made the business of mail routing a complex challenge of backward and forward compatibility for several years. There are now over one million copies of Sendmail installed, representing over 75% of all Internet mail servers.

Simultaneously with the announcement of the company in November 1997, Sendmail 8.9 was launched, featuring new tools designed to limit junk e-mail. SendMail 8.9 is still distributed as source code with the rights to modify and distribute.

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 of ADDRESS. You can also talk to the Sendmail daemon on a remote host FOO with the command

telnet FOO 25


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. (, 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 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.)
References in periodicals archive ?
Cloudmark Inc, one of the tsunami of anti-spam software startups to hit the market the last couple of years, has gone some way to ensuring its continued existence by inking an exclusive OEM deal with Sendmail Inc, which makes the popular email software.
Sendmail, an e-mail security company, has launched its Sendmail Advanced Anti-Spam Filter for companies wishing to cut down on the amount of unwanted e-mails they receive.
Since these attacks violate parameters defined in the RFCs, no configuration changes to the default settings in Symantec's full-application inspection firewalls are required to protect against this Sendmail exploit.
By exploiting the power of Linux on the IBM mainframe platform, Sendmail provides the robustness and scalability needed for today's messaging and mail infrastructure with the industry's lowest total cost of computing.
Eric Allman, the Berkeley graduate student who wrote Sendmail, included a feature so people could mail messages not just to other people but also to other computer programs.
The California-based Internet messaging systems provider Sendmail Inc has acquired the message access software developer Nascent Technologies.
Sendmail Inc has signed an OEM agreement with MessagingDirect Ltd of Edmonton, Canada, a maker of message store and access technologies.
TELECOMWORLDWIRE-9 November 2000-IBM and Sendmail partner to offer highly scalable Internet messaging systems (C)1994-2000 M2 COMMUNICATIONS LTD http://www.
Internet mail server startup Sendmail Inc plans significant expansion into Asian markets.