AS526

AS526 is a legacy 16-bit Autonomous System Number allocated by ARIN to "DNIC-AS-00526 - Headquarters, USAISC" — the U.S. Army Information Systems Command — part of the historic Defense Network Information Center (DNIC) block of military ASN assignments. The ARIN RDAP autnum record's top-level registration event dates the allocation to 1989-09-29, with the record last changed 2011-08-24; the administrative and abuse contact is a DISA (Defense Information Systems Agency) Columbus mailbox, disa.columbus.ns.mbx.arin-registrations@mail.mil, and the registrant address traces to NETC-ANC CONUS TNOSC at Fort Huachuca, Arizona. USAISC itself was inactivated as an Army command in 1996, with its functions folded into successor organizations (eventually U.S. Army Network Enterprise Technology Command, NETCOM); ARIN's registrant name has not been updated to reflect that lineage, so the registry record still reads USAISC. Operationally, AS526 is completely dormant: every routing source checked — RIPEstat, CAIDA AS Rank, bgp.he.net, and bgp.tools — agrees it announces zero IPv4 and zero IPv6 prefixes, has zero visible BGP peers, upstreams, or downstreams, and shows no CAIDA topology presence (customer cone limited to itself, 0 prefixes, 0 addresses). No PeeringDB entry exists for the ASN. No abuse, hijack, route-leak, or NANOG-archive signal was found tying AS526 to any incident.

Operator

Headquarters, USAISC (U.S. Army Information Systems Command), registrant name DNIC-AS-00526, administered by DISA Columbus [Confirmed] — https://rdap.arin.net/registry/autnum/526

Country / RIR

US, ARIN (IANA 16-bit AS block 1-1876, assigned by ARIN) [Confirmed] — https://stat.ripe.net/data/as-overview/data.json?resource=526

Allocated

1989-09-29 (ARIN RDAP autnum top-level registration event, first-party RIR fact); last changed 2011-08-24 [Confirmed] — https://rdap.arin.net/registry/autnum/526 (corroborated independently by two research angles)

Org status

ARIN registration itself is active/valid; the original registrant organization (USAISC) was inactivated as an Army command in 1996, its Fort Huachuca functions later folded into U.S. Army NETCOM, but ARIN's registrant name field has not been updated to reflect that succession

[Confirmed] — https://rdap.arin.net/registry/autnum/526, https://en.wikipedia.org/wiki/Army_Network_Enterprise_Technology_Command

Contacts

disa.columbus.ns.mbx.arin-registrations@mail.mil; registrant address NETC-ANC CONUS TNOSC, Fort Huachuca, AZ 85613, US; admin/abuse contact DISA-Columbus, 300 North James Road, Whitehall, OH 43213, US [Confirmed] — https://rdap.arin.net/registry/autnum/526

Security/abuse context (NEUTRAL, DATED)

not listed in the live Spamhaus ASN-DROP feed (checked 2026-07-10); no NANOG archive threads, BGP hijack/route-leak reports, or botnet/malware reporting found naming AS526

Network & routing

Network type

U.S. Department of Defense / U.S. Army internal government network, legacy DNIC block; not a commercial ISP or hosting provider [Confirmed] — https://rdap.arin.net/registry/autnum/526

Size

dormant — 0 IPv4 and 0 IPv6 announced prefixes; CAIDA customer cone = singleton (1 ASN, 0 prefixes, 0 addresses); CAIDA AS rank 79459 [Confirmed] — https://bgp.he.net/AS526, https://bgp.tools/as/526, CAIDA ASRank

Routing/peering

NOT announced — 0/327 RIS peers seeing IPv4, 0/321 seeing IPv6; no upstreams, peers, or IXP presence observed; no PeeringDB net record exists for AS526 (API query returned 404) [Confirmed] — https://stat.ripe.net/data/routing-status/data.json?resource=526

RPKI

Unknown / not applicable — RPKI validation requires a specific prefix to check against and AS526 announces none [Unknown]

Notable usage

Unknown beyond the RIR record; third-party aggregator ipinfo.io marks it "Inactive" with no peers/upstreams/downstreams as of 2026, consistent with but not itself an operator claim [Likely] — https://ipinfo.io/AS526

Related ASNs

none confirmed; AS525 is a similarly dormant legacy DoD/USAISC-lineage ASN observed in adjacent enrichment work, but no first-party record links the two beyond the shared DNIC block pattern [Unknown]

Analyst note

Dormant legacy DoD ASN with no current routing footprint and no public community discussion; the one solid, verifiable fact beyond dormancy is the 1989-09-29 ARIN allocation date, corroborated by two independent research angles reading the same top-level autnum registration event.