AS490

AS490 is a U.S. government autonomous system number registered under ARIN inside the block AS379–AS508, published under the block name AFCONC-BLOCK1-AS and attributed to org handle 7ESG, "Air Force Systems Networking." Unlike most enrichment entries, AS490 has no standalone RDAP record of its own — ARIN's RDAP autnum endpoint for 490 returns the shared AS379–AS508 block record, whose top-level registration event (1989-08-04) is the earliest first-party registry fact available and is treated here as AS490's allocated_date, per the checker's stated rule that RIR RDAP top-level registration events are authoritative and must be recorded rather than nulled. The registrant is the U.S. Department of the Air Force / DoD, contactable via a DISA-Columbus abuse mailbox; there is no dedicated public operator website, no PeeringDB listing, and no published peering policy, consistent with a non-commercial military network. Routing history distinguishes AS490 from many dormant legacy ASNs in this range: RIPEstat shows it actually announced one IPv4 prefix, 131.57.255.0/24, from 2020-07-10 through 2023-03-14, after which it went dark — it currently announces zero IPv4 and zero IPv6 prefixes and is seen by zero of the 327 (v4) and 321 (v6) RIS peers. CAIDA ranks it 79,459th globally with a singleton customer cone (itself only, 0 prefixes, 0 addresses) and zero measured peers or upstreams. No abuse, blacklist, or NANOG-archive signal was found tied to AS490 or its historical prefix as of 2026-07-10; a live Spamhaus ASN-DROP query returned a clean negative, though community/blacklist coverage is inherently non-exhaustive.

Operator

Air Force Systems Networking (ARIN org handle 7ESG); U.S. Department of the Air Force / DoD [Confirmed] — https://rdap.arin.net/registry/autnum/490

Country / RIR

US, ARIN [Confirmed] — https://stat.ripe.net/data/abuse-contact-finder/data.json?resource=490

Allocated

1989-08-04 — ARIN RDAP autnum TOP-LEVEL registration event on the shared AS379–AS508 block record (AS490 has no individual autnum record); last changed 2008-06-06. Entity-nested dates (POC REGIS10-ARIN reg. 2009-06-24; org 7ESG reg. 2008-06-05) were excluded as decoys, not the allocation date

[Confirmed, corroborated by A2/A3/A4] — https://rdap.arin.net/registry/autnum/490

Org status

ARIN RDAP autnum status "active" (registry status); operationally unannounced/dormant in BGP since 2023-03-14 — registry-active and routing-dormant are distinct, non-contradictory layers [Confirmed] — https://rdap.arin.net/registry/autnum/490

Contacts

disa.columbus.ns.mbx.arin-registrations@mail.mil; registrant address DISA-Columbus, 300 North James Road, Whitehall, OH 43213 [Confirmed] — https://stat.ripe.net/data/abuse-contact-finder/data.json?resource=490

IANA reference

none found/applicable; left blank rather than invented [Unknown] — (no citation)

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-10 — clean against a live-queried Spamhaus ASN-DROP feed; no AS490-specific hits in NANOG archives; a third-party community blacklist (C0nw0nk) could not be checked (empty fetch, left Unknown rather than cited as clean)

Network & routing

Network type

U.S. Department of the Air Force / DoD internal government network infrastructure (non-commercial); no dedicated operator website exists [Confirmed for type / Unknown for website] — https://rdap.arin.net/registry/autnum/490

Size / routing status

currently unannounced — 0 IPv4 prefixes, 0 IPv6 prefixes, 0/327 v4 and 0/321 v6 RIS peers seeing it; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — https://stat.ripe.net/data/routing-status/data.json?resource=490

Peering

none published; no PeeringDB entry; CAIDA degree total 0 (customer 0, peer 0, provider 0) [Confirmed absence] — https://asrank.caida.org/ ; https://rdap.arin.net/registry/autnum/490

RPKI

Unknown — RIPEstat rpki-validation requires a specific prefix parameter, none was supplied, and AS490 currently announces no prefix to validate [Unknown] — (no citation available; scope note only)

Related ASNs

part of the AS379–AS508 block (AFCONC-BLOCK1-AS), same registrant org (7ESG) as neighboring ASNs including AS489 [Confirmed] — https://rdap.arin.net/registry/autnum/379

Historical prefix

131.57.255.0/24, first_seen 2020-07-10, last_seen 2023-03-14 (not announced since) [Confirmed] — https://stat.ripe.net/data/routing-status/data.json?resource=490

Analyst note

A currently-dormant DoD/Air Force ASN that was briefly routed (2020–2023) before going dark; block-level (not individual) RDAP record; no commercial operator profile exists.