Autonomous System

AS721 United States Department of Defense (DoD)

GovernmentActiveUnited StatesARIN

AS721 (DNIC-ASBLK-00721-00726) is a government network operated by United States Department of Defense (DoD) in United States, registered with ARIN. It has 238 IPv4 prefixes with 72,987,904 addresses and 2 IPv6 prefixes, which makes it the 6th largest of 82,334 active autonomous systems by IPv4 space.

IPv4 addresses72,987,904in 238 prefixes
IPv6 prefixes2≈ 1.6 × 10²⁹ addresses
Size rank#6of 82,334 active ASNs
Abuser scoreVery Lowunder 0.01% of its addresses flagged · method

Details

OrganizationUnited States Department of Defense (DoD)
AS nameDNIC-ASBLK-00721-00726
Websitedefense.gov
Country United States (US)
Network typeGovernment
RegistryARIN
Abuse contactdisa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil
Registered—
Last updated2025-09-12

IPv4 prefixes

238 prefixes · 72,987,904 addresses
NetworkAddressesFirst – last address
55.0.0.0/816,777,21655.0.0.0 – 55.255.255.255
214.0.0.0/816,777,216214.0.0.0 – 214.255.255.255
215.0.0.0/98,388,608215.0.0.0 – 215.127.255.255
132.0.0.0/104,194,304132.0.0.0 – 132.63.255.255
131.32.0.0/112,097,152131.32.0.0 – 131.63.255.255
132.96.0.0/112,097,152132.96.0.0 – 132.127.255.255
205.64.0.0/112,097,152205.64.0.0 – 205.95.255.255
132.80.0.0/121,048,576132.80.0.0 – 132.95.255.255
132.128.0.0/121,048,576132.128.0.0 – 132.143.255.255
138.144.0.0/121,048,576138.144.0.0 – 138.159.255.255
131.64.0.0/13524,288131.64.0.0 – 131.71.255.255
137.0.0.0/13524,288137.0.0.0 – 137.7.255.255
138.136.0.0/13524,288138.136.0.0 – 138.143.255.255
143.144.0.0/13524,288143.144.0.0 – 143.151.255.255
158.0.0.0/13524,288158.0.0.0 – 158.7.255.255
160.136.0.0/13524,288160.136.0.0 – 160.143.255.255
160.144.0.0/13524,288160.144.0.0 – 160.151.255.255
205.56.0.0/13524,288205.56.0.0 – 205.63.255.255
205.96.0.0/13524,288205.96.0.0 – 205.103.255.255
131.76.0.0/14262,144131.76.0.0 – 131.79.255.255
131.80.0.0/14262,144131.80.0.0 – 131.83.255.255
136.212.0.0/14262,144136.212.0.0 – 136.215.255.255
136.216.0.0/14262,144136.216.0.0 – 136.219.255.255
137.8.0.0/14262,144137.8.0.0 – 137.11.255.255
137.240.0.0/14262,144137.240.0.0 – 137.243.255.255
The 25 largest of 238. The API and the database have all of them.

IPv6 prefixes

2 prefixes
  • 2608:120::/32
  • 2608:121::/32

Query AS721 with the API

The ASN lookup returns everything on this page as JSON, including every prefix. ASN lookups need an API key: a free account comes with 1,000 requests a day. 

curl "https://api.ipapi.is/?q=AS721&key=YOUR_API_KEY"

Any address in its prefixes resolves to AS721, with or without a key:

curl "https://api.ipapi.is/?q=55.0.0.1"

Other networks of United States Department of Defense (DoD)

6 of 109
AS749 United States Department of Defense (DoD)227,399,168 IPv4 addressesAS56 United States Department of Defense (DoD)8,082,176 IPv4 addressesAS306 United States Department of Defense (DoD)4,666,880 IPv4 addressesAS668 United States Department of Defense (DoD)2,558,464 IPv4 addressesAS5972 United States Department of Defense (DoD)2,298,112 IPv4 addressesAS27064 United States Department of Defense (DoD)1,787,648 IPv4 addresses

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