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.3 Files originating from SIPRNet are marked by a header tag "SIPDIS" (SIPrnet DIStribution).4 A corresponding second-level domain smil.mil exists for DoD users.5
Access is also available to a "...small pool of trusted allies, including Australia, Canada, the United Kingdom and New Zealand...".6 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" release7 as well as the source of the US diplomatic cables published by WikiLeaks in November 2010.8
SIPRNet and NIPRNet are referred to colloquially as SIPPERnet and NIPPERnet (or simply sipper and nipper), respectively.910
Us defense information systems agency handbook. [Place of publication not identified]: Intl Business Pubns Usa. 2007. ISBN 978-1-4330-5548-5. OCLC 946756401. 978-1-4330-5548-5 ↩
"Secret Internet Protocol Router Network (SIPRNET)". Federation of American Scientists' Intelligence Resource Program. Archived from the original on July 26, 1997. Retrieved 12 December 2010. https://web.archive.org/web/19970726161029/http://www.fas.org/irp/program/disseminate/siprnet.htm ↩
"U.S. Department of State Foreign Affairs Handbook Volume 5 Handbook 8 - Web Development Handbook: 5 FAH-8 H-342.2 ClassNet Standards". U.S. Department of State. 29 September 2005. Retrieved 12 Jan 2016. https://fam.state.gov/FAM/05FAH08/05FAH080340.html#H342_2 ↩
"Siprnet: Where the leaked cables came from". BBC. 29 November 2010. Retrieved 19 December 2010. https://www.bbc.co.uk/news/world-us-canada-11863618 ↩
Grimes, John G. (14 April 2008). "Internet Domain Name Use and Approval" (PDF). Department of Defense. Archived from the original (PDF) on August 21, 2010. https://web.archive.org/web/20100821164020/http://www.dtic.mil/whs/directives/corres/pdf/841001p.pdf ↩
Field, Michael (2 December 2010). "NZ way down the WikiLeaks queue". Fairfax New Zealand. Retrieved 17 December 2010. http://www.stuff.co.nz/national/4415037/NZ-way-down-the-WikiLeaks-queue ↩
Poulsen, Kevin; Zetter, Kim (6 June 2010). "U.S. Intelligence Analyst Arrested in Wikileaks Video Probe". Wired. Retrieved 15 June 2010. https://www.wired.com/threatlevel/2010/06/leak/ ↩
Leigh, David (28 November 2010). "US embassy cables leak sparks global diplomacy crisis". The Guardian. Retrieved 28 November 2010. https://www.theguardian.com/world/2010/nov/28/us-embassy-cable-leak-diplomacy-crisis ↩
"Definition of NIPRNet". PCMag. n.d. Retrieved 18 August 2021. https://www.pcmag.com/encyclopedia/term/niprnet ↩
Harold F. Tipton; Micki Krause Nozaki (2010). Information Security Management Handbook, Volume 4 (6th ed.). CRC Press. p. 67. ISBN 9781439819036. 9781439819036 ↩