Sendmail

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This article is about the mail transfer agent. For the company, see Sendmail, Inc..
Sendmail
Sendmail.org small logo.gif
Developer(s) Sendmail Consortium, Sendmail, Inc.
Stable release 8.15.2 Release Notes / July 3, 2015 (2015-07-03)
Operating system Cross-platform
Type Mail transfer agent
License Sendmail License
Website http://www.sendmail.org/

Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet.

A descendant of the delivermail program written by Eric Allman, Sendmail is a well-known project of the free and open source software and Unix communities. It has spread both as free software and proprietary software.

Overview[edit]

Allman had written the original ARPANET delivermail which shipped in 1979 with 4.0 and 4.1 BSD. He wrote Sendmail as a derivative of delivermail in the early 1980s at UC Berkeley. It shipped with BSD 4.1c in 1983, the first BSD version that included TCP/IP protocols.

In 1996, approximately 80% of the publicly reachable mail-servers on the Internet ran Sendmail.[1] More recent surveys have suggested a decline, with 8.86% of mail servers in April 2014 detected as running Sendmail in a study performed by E-Soft, Inc.[2]

Allman designed Sendmail to incorporate great flexibility, but it can be daunting to configure for novices.[3] Standard configuration packages delivered with the source code distribution require the use of the M4 macro language which hides much of the configuration complexity. The configuration defines the site-local mail delivery options and their access parameters, the mechanism of forwarding mail to remote sites, as well as many application tuning parameters.

Sendmail supports a variety of mail transfer protocols, including SMTP, ESMTP, DECnet's Mail-11, HylaFax, QuickPage and UUCP. Additionally, Sendmail v8.12 as of September 2001 introduced support for milters - external mail filtering programs that can participate in each step of the SMTP conversation.

Acquisition by Proofpoint, Inc.[edit]

Sendmail, Inc was acquired by Proofpoint, Inc. This announcement was released on 1 October 2013. [4]

Sendmail 8 releases[edit]

The information derives from RELEASE_NOTES file from sendmail distribution.

Security[edit]

Sendmail originated in the early days of the Internet, an era when considerations of security did not play a primary role in the development of network software.[citation needed] Early versions of Sendmail suffered from a number of security vulnerabilities that have been corrected over the years.

Sendmail itself incorporated a certain amount of privilege separation in order to avoid exposure to security issues. As of 2009, current versions of Sendmail, like other modern MTAs, incorporate a number of security improvements and optional features that can be configured to improve security and help prevent abuse.

History of vulnerabilities[edit]

Sendmail vulnerabilities in CERT advisories and alerts:

The UNIX-HATERS Handbook dedicated an entire chapter to perceived problems and weaknesses of sendmail.

Implementation[edit]

As of sendmail release 8.12.0 the default implementation of sendmail runs as the Unix user smmsp[5] — the sendmail message submission program.

See also[edit]

Notes[edit]

  1. ^ D. J. Bernstein (1996-11-27). "Internet host SMTP server survey". 
  2. ^ "E-Soft MX survey". 
  3. ^ "Sendmail Installation and Operations Guide" (PDF). 
  4. ^ "Proofpoint, Inc. Acquires Sendmail, Inc.". 
  5. ^ "Sendmail release notes". sendmail.org. The Sendmail Consortium. Retrieved 2009-08-30. 

References[edit]

External links[edit]