AS573

AS573 is a legacy autonomous system number registered under ARIN's DNIC (Defense Network Information Center) block to the United States Department of Defense, with day-to-day contact handling delegated to the Defense Information Systems Agency's Columbus, Ohio hostmaster office. ARIN's autnum record shows a top-level registration event dated 1990-01-31, distinct from several later contact-record dates (a NOC entity registered 1993, a registrations entity registered 2009, and an org-entity record touched again in 2007/2025) that belong to individual WHOIS contacts rather than the ASN allocation itself. Operationally, AS573 is registered but not currently routed: RIPEstat reports zero announced IPv4 and IPv6 prefixes across its query window, with none of 327 or 322 sampled RIS peers observing it, and CAIDA's AS Rank dataset shows a customer cone containing only the ASN itself, with zero observed peers, providers, or customers. No PeeringDB listing exists for AS573, and no public peering policy could be located, consistent with a closed military network rather than a commercial transit or access provider. No notable public abuse or threat-intelligence signal was found, plausibly because an unrouted ASN generates little to no observable Internet traffic. RPKI validation does not apply since there is no announced prefix to check against a ROA.

Operator

United States Department of Defense (DoD); registry name DNIC-AS-00573; administrative/technical/abuse contact is DISA-Columbus (Defense Information Systems Agency) [Confirmed] — https://rdap.arin.net/registry/autnum/573

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/573 ; abuse-contact-finder authoritative_rir arin, https://stat.ripe.net/AS573

Allocated

1990-01-31 (ARIN RDAP autnum TOP-LEVEL "registration" event); last changed 2025-09-12 (top-level "last changed" event) [Confirmed, corroborated by two independent angles] — https://rdap.arin.net/registry/autnum/573. Note: entity-level dates under the record (MIL-HSTMST-ARIN entity registered 1993-05-26; REGIS10-ARIN entity registered 2009-06-24; USDDD org-entity registered 2007-01-12 / last changed 2025-03-13) are contact-record dates, not the ASN's own allocation date, and were excluded as decoys.

Org status

active [Confirmed] — https://rdap.arin.net/registry/autnum/573. Registrant address: United States Department of Defense (DoD), 3990 E. Broad Street, Columbus, OH 43218, US; DISA-Columbus contact address 300 North James Road, Whitehall, OH 43213, US

[Confirmed] — https://rdap.arin.net/registry/autnum/573

Contacts

disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil (abuse); disa.columbus.ns.mbx.arin-registrations@mail.mil (registrations); phone +1-844-347-2457 ext2 [Confirmed] — https://stat.ripe.net/AS573, https://rdap.arin.net/registry/autnum/573

Security/abuse context (NEUTRAL, DATED)

no notable public abuse or threat-intelligence signal found as of 2026-07-11; consistent with the ASN's unrouted status giving it little observable Internet-facing surface

Network & routing

Network type

closed U.S. government/military network within the DNIC block, part of the DoD Information Network (DODIN); not a commercial transit/access provider [Likely] — https://rdap.arin.net/registry/autnum/573, https://en.wikipedia.org/wiki/Defense_Information_Systems_Agency

Size

not currently routed — 0 IPv4 prefixes / 0 IPv4 addresses and 0 IPv6 prefixes announced; CAIDA customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — https://stat.ripe.net/AS573, https://api.asrank.caida.org/v2/restful/asns/573

Routing/peering

NOT announced — 0 of 327 RIS peers see it in v4, 0 of 322 in v6; CAIDA degree total 0 (customer 0, peer 0, provider 0); no PeeringDB listing exists (confirmed 404) and no public peering policy found

[Confirmed] — https://stat.ripe.net/AS573, https://api.asrank.caida.org/v2/restful/asns/573, https://www.peeringdb.com/asn/573

RPKI

not assessable/not applicable — AS573 announces no prefixes, so there is no ROA-vs-announcement validation surface [Confirmed] — https://stat.ripe.net/AS573

Notable usage

Unknown beyond general DoD DNIC allocation; no operator-published detail distinguishing this ASN's specific use from DoD's other DNIC ASNs was found [Unknown]

Related ASNs

Unknown — no specific sibling DNIC ASN list independently verified in this cycle

Analyst note

CAIDA's lat/long fields read 0,0 — an unset placeholder, not a real geolocation, so geo footprint is reported from the RIR registrant/contact addresses instead. disa.mil could not be independently confirmed as rendering DISA content in this cycle (fetch returned an unrelated placeholder page), so operator-site claims about DISA's role rest on a secondary source and are tagged Likely rather than Confirmed.