The top-level domain (TLD) “.mil” is a domain that is specifically reserved for the United States Department of Defense (DoD) and its subsidiary or affiliated organizations. It was one of the first TLDs established in January 1985 and has been in use ever since.
A top-level domain is the highest level of domain names in the root zone of the Domain Name System (DNS) of the Internet. In general, TLDs are either categorized as Generic Top-Level Domains (gTLDs), such as .com, .edu, and .org, or Country Code Top-Level Domains (ccTLDs), like .uk for the United Kingdom or .jp for Japan. There are also sponsored top-level domains (sTLDs) such as .aero, .coop, and .museum, which are proposed and sponsored by private agencies or organizations that establish and enforce rules restricting the eligibility to use the TLD.
However, .mil is a unique case. Instead of being a gTLD, ccTLD, or sTLD, .mil is a restricted top-level domain specifically reserved by the United States. In particular, this TDL is strictly for the U.S. military. It’s worth mentioning that .mil is the only TLD that is explicitly limited to a single organization.
The usage of this TLD can be seen in various official military websites like www.army.mil (for U.S. Army), www.navy.mil (for U.S. Navy), www.marines.mil (for the U.S. Marine Corps), and www.defense.gov (for Department of Defense). Other official bodies linked to the U.S. military also use this TLD, such as www.jcs.mil for the Joint Chiefs of Staff and www.usafa.af.mil for the United States Air Force Academy.
These different websites provide various information from the respective branches. For instance, you can find news, leadership bios, details about history and heritage, photos, videos, details of operations, and even contact information.
The .mil TLD is managed by the Defense Information Systems Agency (DISA), an agency of the Department of Defense. According to DISA policies, the .mil TLD can only be given to organizations, units, or activities of the DoD that are located in the U.S., or overseas units that are recognized by international law.
In summary, the .mil TLD, unlike most other TLDs, is specifically confined to the U.S. military and its associated entities, making it a unique part of the domain name system of the Internet.
Sources:
1. Kosters, Mark, and Huston, Geoff. “The .mil Top-level Domain.” Accessed February 15, 2021.
2. Defense Information Systems Agency (DISA) “DISA Policies.” Accessed February 15, 2021.
3. “IANA — .mil Domain Delegation Data”. www.iana.org. Retrieved 15 February 2021.
4. “RFC 920, Domain Requirements – Specifying the rules for delegating domains in the DNS”. Accessed February 15, 2021.
