AS451

AS451 is a legacy autonomous system number administered under ARIN to Air Force Systems Networking, the network organization associated with the U.S. Air Force's 754th Electronic Systems Group (Department of Defense). ARIN does not expose a per-ASN RDAP object for AS451; instead the number falls inside a single block registration object — handle AS379, name AFCONC-BLOCK1-AS, spanning startAutnum 379 through endAutnum 508 — under which ARIN issues legacy DoD AS ranges collectively. The registrant of record (ARIN org handle 7ESG) is listed as Air Force Systems Networking at 501 East Moore Dr., Bldg 884, Gunther Annex, Maxwell AFB, AL 36114, with the abuse contact routed to DISA's ARIN-registrations mailbox in Columbus. The key triage point is that AS451 is effectively dark today: RIPEstat routing-status shows zero prefixes announced and 0 of 325 IPv4 RIS peers (and 0 of 321 IPv6 peers) currently seeing it, with the last historical sighting on 2025-07-15 (prefix 199.225.4.0/24) and a first sighting back in 2001 (132.5.0.0/16). CAIDA AS Rank corroborates the inactivity: rank 79,459, a singleton customer cone (itself, 0 prefixes, 0 addresses), and an AS degree of zero across customer, peer, and provider. RPKI posture is not assessable because no prefixes are being originated. No notable public abuse signal was found as of July 2026 — not in Spamhaus ASN-DROP or general abuse feeds — consistent with a dormant, non-commercial government ASN rather than a flagged network.

Operator

Air Force Systems Networking (U.S. Air Force / 754th Electronic Systems Group, Department of Defense; ARIN org handle 7ESG, Maxwell AFB, AL) [Confirmed] — ARIN RDAP autnum/451, bgp.he.net/AS451

Country / RIR

US, ARIN [Confirmed] — RIPEstat abuse-contact-finder (authoritative_rir: arin)

Allocated

1989-08-04 (ARIN registry date from the autnum TOP-LEVEL registration event; block-level for AS379–AS508 / AFCONC-BLOCK1-AS, NOT an IEEE date — IEEE publishes no ASN registration dates); last changed 2008-06-06 [Confirmed] — ARIN RDAP autnum/451 top-level events

Org status

active U.S. Department of Defense / Air Force organization (Air Force Systems Networking, tied to the 754th Electronic Systems Group) [Confirmed] — ARIN RDAP autnum/451, hanscom.af.mil

Contacts

abuse disa.columbus.ns.mbx.arin-registrations@mail.mil; registrant 501 East Moore Dr., Bldg 884 Rm 1100 Gunther Annex, Maxwell AFB, AL 36114, US [Confirmed] — RIPEstat abuse-contact-finder, ARIN RDAP autnum/451

Website

no dedicated operator-official page for this ASN or block located (af.mil / disa.mil searched) [Unknown]

IANA reference

none — no IANA special-purpose RFC reference applies to this ASN (field left blank per no-fabrication rule) [Unknown]

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-02 — not in Spamhaus ASN-DROP or general abuse feeds; Scamalytics aggregate for "Air Force Systems Networking" shows low fraud-risk; dormant government network

Network & routing

Network type

U.S. military/government (DoD, Air Force) internal network infrastructure; AS451 is legacy/inactive [Confirmed] — ARIN RDAP autnum/451 (registrant Maxwell AFB, Gunther Annex)

Size

dormant — 0 IPv4 prefixes / 0 IPv4 addresses and 0 IPv6 prefixes announced; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses [Confirmed] — RIPEstat routing-status / announced-prefixes / CAIDA AS Rank (2026-07)

Routing/peering

NOT announced — 0 RIS peers seeing it (0/325 v4, 0/321 v6); CAIDA degree total 0 (customer 0, peer 0, provider 0); no upstreams or peers visible; RIPEstat observed_neighbours 0 [Confirmed]. No published peering policy (not expected for a non-commercial DoD ASN) [Unknown]

RPKI

not assessable — AS451 announces no prefixes, so there are no ROAs to validate; RIPEstat rpki-validation requires a prefix and none exist [Confirmed]

Notable usage

historically originated 132.5.0.0/16 (first seen 2001-09-26) and later 199.225.4.0/24 (last seen 2025-07-15); no IPv6; now withdrawn/dark. bgp.he.net reports it not visible in the global table since ~2025-08-04 [Likely] — RIPEstat routing-status, bgp.he.net/AS451

Related ASNs

AS379–AS508 all fall under the same ARIN block object AFCONC-BLOCK1-AS (Air Force Systems Networking) [Confirmed for block membership] — ARIN RDAP autnum/451

Analyst note

Encountered as a dormant legacy DoD ASN with no per-ASN RDAP record; the 1989-08-04 date is a first-party ARIN registry fact recorded at block granularity (AS379–AS508), not an AS451-unique issuance date. Clean, inactive, government-held.