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SIPRNet

Computer network used by the United States Government

Wikipedia contributorsAdapted for Fathomly · View authors
1 min read
Source updated August 30, 2026
Image credit is listed at the end of this article.

The Secret Internet Protocol Router Network (SIPRNet) is "a system of interconnected computer networks used by the U.S. Department of Defense and the U.S. Department of State to transmit classified information (up to and including secret information) by packet switching over the 'completely secure' environment". It also provides services such as hypertext document access and electronic mail.

SIPRNet is a component of the Defense Information Systems Network. Other components handle communications with other security needs, such as the NIPRNet, which is used for nonsecure communications, and the Joint Worldwide Intelligence Communications System (JWICS), which is used for Top Secret communications.

01Access

According to the U.S. Department of State Web Development Handbook, domain structure and naming conventions are the same as for the open internet, except for the addition of a second-level domain, like, e.g., "sgov" between state and gov: openforum.state.sgov.gov. Files originating from SIPRNet are marked by a header tag "SIPDIS" (SIPrnet DIStribution). A corresponding second-level domain smil.mil exists for DoD users.

Access is also available to a "...small pool of trusted allies, including Australia, Canada, the United Kingdom and New Zealand...". This group (including the US) is known as the Five Eyes.

SIPRNet was one of the networks accessed by Chelsea Manning, convicted of leaking the video used in WikiLeaks' "Collateral Murder" release as well as the source of the US diplomatic cables published by WikiLeaks in November 2010.

Behind the Green Door secure communications center with SIPRNET, GWAN, NSANET, and JWICS access
Behind the Green Door secure communications center with SIPRNET, GWAN, NSANET, and JWICS access

02Alternate names

SIPRNet and NIPRNet are referred to colloquially as SIPPERnet and NIPPERnet (or simply sipper and nipper), respectively.

Watch videos about SIPRNetExplainers and documentaries on YouTube (opens in a new tab)

Sources and credits

This article is adapted from the Wikipedia article “SIPRNet”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

Images, from Wikimedia Commons:

  • USDoS 136760 header.png by Antonio O. Garza, Jr. U.S. Ambassador to Mexico, Public domain
  • Intel GreenDoor.jpg by Director of National Intelligence (DNI) & Special Security Office, Office of the deputy chief of staff, G-2, Pentagon, Public domain

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Related topics

CAVNET

CAVNET, short for Cavalry Intranet was a secure military forum developed by the 1st Cavalry Division which became operational in April 2004. A part of SIPRNet, it allows fast access to knowledge acquired on the ground in combat.

Classified United States website

A variety of networks operating in special security domains handle classified information in the United States or sensitive but unclassified information, while other specialized networks are reserved specifically for unclassified use by the same agencies. Some sites accessed from these networks have been referred to as "classified websites" in official communications, such as the American embassy "Amman's Classified Web Site at http://www.state.sgov.gov/pinea/amman/" and "Mexico City's Classified Web Site at http://www.state.sgov.gov/p/wha/mexicocity" Some of these trace back to the Defense Data Network which split from the Internet in 1983.

NIPRNet

The Non-classified Internet Protocol Router Network (NIPRNet) is an IP network used to exchange unclassified information, including information subject to controls on distribution, among the private network's users. The NIPRNet also provides its users access to the Internet.