AS539

AS539 is a legacy Defense Network Information Center (DNIC) autonomous system registered under ARIN to "Headquarters, USAISC" — the U.S. Army Information Systems Command — with a registrant address at Fort Huachuca, Arizona, and technical/abuse/administrative contacts routed to a DISA-Columbus mailbox in Whitehall, Ohio. The ARIN RDAP autnum record's top-level registration event dates the allocation to 1989-09-29, with the record itself last touched 2011-08-02. USAISC as a named command was inactivated in 1996, its mission folded into U.S. Army Signal Command and later NETCOM, but the ARIN registration string persists unchanged, which is typical of dormant DoD legacy AS number blocks. Routing evidence is unambiguous: RIPEstat and CAIDA both show zero IPv4/IPv6 prefixes currently announced, zero visible peers, zero upstreams, and a customer cone limited to the ASN itself. Historically it announced 204.208.0.0/16-range /24 blocks between 2002-08-15 and 2017-05-19, then dropped out of the global routing table entirely. No public abuse, hijack, or blocklist signal was found for AS539 as of 2026-07-10, consistent with a dormant, low-profile military stub allocation rather than an actively managed commercial network.

Operator

Headquarters, USAISC (U.S. Army Information Systems Command); ARIN org handle HEADQU-3, registrant address Fort Huachuca, AZ [Confirmed] — https://rdap.arin.net/registry/autnum/539

Country / RIR

US, ARIN [Confirmed] — https://stat.ripe.net/AS539 (abuse-contact-finder authoritative_rir: arin)

Allocated

1989-09-29 (ARIN RDAP autnum TOP-LEVEL registration event — first-party RIR fact, distinct from the nested HEADQU-3 registrant-entity registration date of 1990-03-26, which is an org-record decoy, not the ASN's own date); last changed 2011-08-02 (autnum top-level "last changed" event)

[Confirmed] — https://rdap.arin.net/registry/autnum/539

Org status

registration remains on file at ARIN (autnum record last changed 2011-08-02; the nested HEADQU-3 org record was separately touched 2025-03-13), but the named operator (USAISC) was inactivated in 1996 with its mission absorbed by U.S. Army Signal Command / NETCOM — the ASN is operationally dormant though the registry entry persists

[Likely] — https://whois.arin.net/rest/org/HEADQU-3, https://en.wikipedia.org/wiki/Army_Network_Enterprise_Technology_Command

Contacts

disa.columbus.ns.mbx.arin-registrations@mail.mil (technical/abuse/administrative, entity REGIS10-ARIN, DISA-Columbus, Whitehall, OH) [Confirmed] — https://rdap.arin.net/registry/autnum/539

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-10 across general web search of Spamhaus, Hurricane Electric, and NANOG community archives; no BGP hijack, route leak, or blocklist report located. General-search absence-of-evidence, not a direct authoritative-list API query

Network & routing

Network type

U.S. federal/military network — DNIC (Defense Network Information Center) legacy allocation block (AS name "DNIC-AS-00539"), currently dormant/unannounced [Confirmed] — https://rdap.arin.net/registry/autnum/539

Size

dormant — 0 IPv4 and 0 IPv6 prefixes currently announced; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — https://stat.ripe.net/AS539, CAIDA ASRank API (https://api.asrank.caida.org/v2/restful/asns/539)

Routing/peering

NOT currently announced — 0 of 325 RIS v4 peers and 0 of 322 v6 peers see it; CAIDA degree total 0 (customer 0, peer 0, provider 0); no PeeringDB record exists for AS539 [Confirmed]. Historical BGP (Hurricane Electric) shows one past observed peer, AS27066 (U.S. DoD Network Information Center), no longer active

[Likely] — https://bgp.he.net/AS539, https://api.asrank.caida.org/v2/restful/asns/539

RPKI

not assessable — AS539 announces no prefixes today, so there are no ROAs to validate against; RIPEstat's rpki-validation endpoint requires a prefix parameter and was skipped [Unknown] — https://stat.ripe.net/AS539

Notable usage

originated 204.208.18.0/24 through 204.208.118.0/24-range blocks between 2002-08-15 (first seen) and 2017-05-19 (last seen); not observed in the global routing table since [Confirmed] — https://stat.ripe.net/AS539

Related ASNs

none confirmed from available sources; part of the broader DNIC-AS-00xxx legacy DoD block series held by Army commands [Unknown]

Analyst note

A single-source website/peering-policy field (no operator-official site exists for this inactivated command) is tagged Unknown rather than fabricated; all routing and registry facts are corroborated by two or more independent angles (RIPEstat + CAIDA + ARIN RDAP).