AS533

AS533 is a legacy autonomous system number registered under ARIN as DNIC-AS-00533, part of the Defense Network Information Center (DNIC) block of ASNs allocated to U.S. Department of Defense components in the early Internet era. The registrant of record is "Headquarters, USAISC" — the U.S. Army Information Systems Command, a command headquartered at Fort Huachuca, Arizona that was inactivated in 1996, with its functions absorbed into successor Army signal/network organizations. Despite that 1996 inactivation, the ARIN registration record for AS533 was never modernized or reassigned: the registrant name still reads "Headquarters, USAISC," while day-to-day administrative, technical, and abuse contact duties have been delegated to a DISA-Columbus registration mailbox at Whitehall, Ohio, consistent with how DISA centrally manages many legacy DoD-held ASNs and address blocks today. Every routing data source consulted — RIPEstat, bgp.he.net, bgp.tools, and CAIDA AS Rank — agrees AS533 currently announces zero IPv4 and zero IPv6 prefixes, has zero observed BGP peers or upstreams, and sits in a customer cone of exactly one ASN (itself). This is consistent with a dormant, held-in-reserve military ASN rather than one supporting live public-Internet-facing infrastructure. No PeeringDB record exists for AS533, and no public abuse or security incident history was found tied to this ASN as of 2026-07-10.

Operator

Headquarters, USAISC (U.S. Army Information Systems Command); registrant org handle HEADQU-3, address NETC-ANC CONUS TNOSC, Fort Huachuca, AZ 85613 [Confirmed] — https://rdap.arin.net/registry/autnum/533

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/533 ; RIPEstat abuse-contact-finder (authoritative_rir: arin)

Allocated

1989-09-29 (ARIN RDAP autnum TOP-LEVEL "registration" event, timestamp 1989-09-29T00:00:00-04:00 — first-party registry fact, not the nested entity/POC dates); last changed 2011-08-24 [Confirmed, corroborated independently by bgp.tools stating "Registered September 29, 1989"] — https://rdap.arin.net/registry/autnum/533 , https://bgp.tools/as/533

Org status

ARIN registry status "active" (administratively active registration), but operationally dormant; registrant remains "Headquarters, USAISC" despite that command's 1996 inactivation — typical for un-modernized legacy DoD ASN registrations; no confirmed successor operator on record [Confirmed for RDAP status; Likely for the USAISC-inactivation context] — https://rdap.arin.net/registry/autnum/533 , https://en.wikipedia.org/wiki/United_States_Army_Information_Systems_Engineering_Command

Contacts

disa.columbus.ns.mbx.arin-registrations@mail.mil; +1-844-347-2457 ext 2; DISA-Columbus, 300 North James Road, Whitehall, OH 43213 (roles: technical, abuse, administrative) [Confirmed] — https://rdap.arin.net/registry/autnum/533

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-10 — AS533 absent from the live Spamhaus ASN-DROP feed; no relevant NANOG-archive, seclists.org, or BGP hijack/route-leak coverage found; consistent with a DoD-registered ASN with no public abuse surface

Network & routing

Network type

U.S. military/DoD (Army) legacy DNIC-block ASN; currently dormant/unannounced, not operationally live on the public Internet [Confirmed] — https://rdap.arin.net/registry/autnum/533

Size

0 IPv4 prefixes / 0 IPv4 addresses; 0 IPv6 prefixes; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — https://stat.ripe.net/AS533 , https://bgp.he.net/AS533 , https://asrank.caida.org/asns/533

Routing/peering

NOT announced — 0/325 RIS peers seeing v4, 0/322 seeing v6, 0 observed neighbours; CAIDA AS degree total 0 (customer 0, peer 0, provider 0); no upstreams visible; no PeeringDB net record found

[Confirmed] — https://stat.ripe.net/AS533 , https://bgp.he.net/AS533 , https://bgp.tools/as/533 , https://asrank.caida.org/asns/533

RPKI

not assessable — AS533 announces no prefixes, so there are no ROAs to validate [Confirmed] — https://bgp.he.net/AS533

Notable usage

None identified; not seen in the global BGP routing table, no IXP presence, appears held in reserve as a legacy DoD/DNIC registration rather than actively operated [Likely] — https://bgp.tools/as/533

Related ASNs

None identified/confirmed in this pass [Unknown]

Analyst note

Legacy 1989 DoD/Army DNIC-block ASN, registrant of record unchanged since a command inactivated in 1996; zero live BGP footprint across all sources consulted; clean, dormant, no abuse history found.