AS5721 National Defense University

NDU-NET - National Defense University · registered in the United States

IPv4 addresses5121 prefixes · <0.001% of announced IPv4

Rank in United States#10,560largest network in US by IPv4 space, of 18,338 · <0.01% of US

Rank worldwide#49,561of 79,396 networks with IPv4

IPv6noneno IPv6 routes announced

CountryUnited States18,679 ASNs registered there

Open AS5721 in ASN lookup Look up an IP in this network (216.21.18.1) All networks in United States

IPv4 prefixes

All 1 prefix, in address order.

216.21.18.0/23

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ASNNameIPv4 addresses

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AS5705#10559 COLUMBIA-CREDIT-UNION - Columbia Community Credit Union512

AS5728#10561 WORLDNET1 - AT&T Enterprises, LLC512

AS5790#10562 NETMARKET - Trilegiant Corporation512

AS5860#10563 DNIC-ASBLK-05800-06055 - United States Department of Defense (DoD)512

IP-to-ASN data: iptoasn.com (public domain). Snapshot downloaded 2026-11-11, refreshed daily. Ranges are what each network announces in BGP, not registry allocations. Data sources