Autonomous system
AS5721 NDU-NET
Unclassified ARIN
Summary
National Defense University
government military education legacy
The network of the National Defense University, the US Department of Defense's joint professional military education institution in Washington, DC, under the handle NDU-NET.
What it's used for
- Connectivity for a DoD university that educates senior military officers and civilian officials, spanning its constituent colleges and research centres.
- Originates two /24s out of
216.21.18.0/23— a compact footprint for a single campus.
Notable
- A government and military address space, but an academic one: this is a degree- granting institution under DoD, not an operational or tactical network.
- ARIN records date the organisation to 1994 and the AS number to 1995, so unlike many low numbers in this range it is an original assignment, not a modern reissue.
This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy. Source, and how to suggest an edit.
Interconnection
Peering at a glance
Internet exchanges
No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-19, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 1 prefixes · 512 addresses IPv6 0 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 1 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS5721- Registry name
- NDU-NET
- Registrant
- National Defense University
- Abuse contact
- chris.hartley.ctr@ndu.edu
- Registered
- 1995-09-06
- Last changed
- 2015-05-07
- Allocation
- assigned
Routing security
RPKI and IRR
- RPKI
- 0% valid · 0 valid, 2 with no ROA
- ROAs
- 0 authorising AS5721
- ASPA
- no ASPA record
- IRR
- 0% registered · 0 of 2 announcements 1 other origin
- Route objects
- 0 naming AS5721
Reputation
Classification and threat
Unclassified Not in the curated lists. Most of the ~80,000 allocated ASNs are not.
Spamhaus DROP
Not on ASN-DROP The network as a whole is not listed.
No DROP prefixes None of its announced space is on the DROP prefix list.
Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 442 networks and 1,783 prefixes, as published 2026-10-20. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.
FBI IC3
No IC3 indicators Nothing from the FBI IC3 feed.
IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.
Elsewhere