The Secret Internet Protocol Router Network (SIPRNet)

The Secret Internet Protocol Router Network (SIPRNet) is basically a secure network that is used by the United States Department of Defense (DoD) and the United States Department of State (DoS) to distribute classified information and communicate amongst each other. SIPRNet is nearly identical to any other standard TCP/IP network; it originated from the same predecessor as the internet, the Advanced Research Projects Agency Network (ARPANET). Of course there are major enhancements in the security design of the network such as the implementation of strong crypto throughout the whole network but for the most part SIPRNet and the Internet are nearly the same, just air gapped from each other. SIPRNet has many of the same services that the Internet has such as hypertext document access and electronic mail. Classified information up to and including the “Secret” level is allowed to be transmitted on SIPRNet. For those of you who don’t know the “Secret” level is the second-highest classification level of the United States government classification system. Information that has been classified at this level would cause “serious damage” to national security if disclosed and not first authorized. According to the Pentagon, SIPRNet has approximately 4.2 million users. These users are spread throughout the world and are in countries that are a part of FVEY. SIPRNet was one of the networks that was accessed by Chelsea Manning who leaked the video used on WikiLeaks “Collateral Murder”. Manning also was the source of the US diplomatic cables published by WikiLeaks in November 2010.


The SIPRNet Verses the Internet
While I have said this before in my articles and am sure I will say it again, there is not one Internet there are many Internets. The Internet is broken down into so many different ‘pieces.’ Just look at how many different LANs or private networks there are: governments, enterprises, colleges, universities, and so on. While many people might refer to these LANs as Intranets, the reality is that even though these networks are operating off of private address ranges some of them are big enough to be their own small Internet. If you want to look at this from a larger point of view then just zoom out a bit and look at the Internet from a global perspective. When you look at things from a global perspective you will notice that it is all about control and power. Now try to look at the Internet from a power perspective. China is a great example of a country that is all about power and control over their Internet, not of control of the whole world just their citizens. If you have not already read my article Internet Censorship in China or “The Great Firewall of China” you should, as it goes more in depth about Internet censorship in China. You could literally break the Internet down by different countries and legal jurisdictions to see that although it for the most part is physically connected it is all controlled in different ways by many different governments and organizations. With all that said SIPRNet is yet another example of how there is not only one Internet. SIPRNet is a government owned IP network which is designed to be air gapped from the Internet and any other TCP/IP networks; however, there are gateways which will allow you to connect to SIPRNet from the Internet. So even though SIPRNet is for the most part physically separate from the Internet it does have points where it connects to the Internet. All communication on SIPRNet is done over wired connections (no radio, no satellite links); SIPRNet also has its own dedicated lines which include both worldwide submarine communications cable and terrestrial cables. One of the reasons SIPRNet is considered a separate Internet is because it is government owned and operated unlike the civilian Internet. We need to start thinking of the Internet as many different Internets which are all controlled and powered by different authorities, this will help to simplify things in the security realm. According to the U.S. Department of State Web Development Handbook the DNS structure of SIPRNet is the same as on the Internet except for the addition of a second-level domain, an example of this would be “sgov” (between state and gov)


The SIPRNet and Other Government Owned IP Networks
There are many other government owned IP networks such as the Nonsecure Internet Protocol Router Network (NIPRNet), the Releasable Internet Protocol Router Network (RIPRNet), the Joint Worldwide Intelligence Communications System (JWICS), and many more. There are also other government owned networks which are not for sharing classified information such as the Energy Sciences Network (ESnet) which serves scientists at the United States Department of Energy and is run by staff at the Lawrence Berkeley National Laboratory. ESnet is made for educational related purposes unlike SIPRNet and other networks like it which are made for sharing classified government documents.


Thank you for taking the time to read this article! As always keep the faith!

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Preston Hood
Hello, my name is Preston Hood. I am the owner of PJHoodsCo, an Information Technology Service Provider (ITSP). I am also a freelance writer and information security researcher.
Preston Hood

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