AS423

AS423 is a legacy autonomous system number registered under ARIN to Air Force Systems Networking (AFSN), a U.S. Department of Defense / U.S. Air Force network organization. It is not an individually-delegated, operator-branded ASN: it sits inside ARIN's block-level registration AFCONC-BLOCK1-AS (Air Force Consolidated Block 1), which spans the range AS379–AS508 under a single autnum record (RDAP handle AS379, registrant org handle 7ESG). The triage point for AS423 is that it is entirely dormant in the global routing table. Every routing source consulted agrees it announces zero IPv4 and zero IPv6 prefixes: RIPEstat reports 0 of 324 RIS peers seeing it on IPv4 and 0 of 320 on IPv6, CAIDA AS Rank shows an all-zero AS degree (0 customer, 0 peer, 0 provider), a customer cone of just itself (1 ASN, 0 prefixes, 0 addresses), seen=false in topology, and an AS rank of 79,459 near the bottom of the global ranking. There is no PeeringDB network record for AS423 specifically (both /api/net?asn=423 and /asn/423 return HTTP 404), and the operator's PeeringDB org page (id 20118) lists AS65/123/175/221/301 but not AS423 — consistent with a non-participating government block. RPKI posture is not assessable because there are no announced prefixes and therefore no ROAs to validate. The registered abuse contact is DISA Columbus's ARIN registrations mailbox. No notable public abuse signal was found as of 2026-07-02: AS423 does not appear in Spamhaus ASN-DROP, and no NANOG-archive or BGP-hijack report names it. This is a clean, unrouted DoD-block ASN, matching the AFCONC-BLOCK1-AS holder pattern seen across the adjacent AS379–AS508 range.

Operator

Air Force Systems Networking (AFSN); U.S. Department of Defense / U.S. Air Force; ARIN registrant org handle 7ESG [Confirmed] — ARIN RDAP autnum/423, whois.arin.net/rest/asn/AS423

Country / RIR

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

Allocated

1989-08-04 (ARIN RDAP autnum TOP-LEVEL registration event for the AFCONC-BLOCK1-AS block AS379–AS508 containing AS423 — a first-party RIR fact, NOT an IEEE date); last changed 2008-06-06 [Confirmed] — ARIN RDAP autnum top-level events (entity-level events REGIS10-ARIN 2009-06-24 and org 7ESG 2008-06-05 excluded as decoys)

Org status

active per ARIN registry (block AS379–508 status Active) but operationally dormant (no announced routes/peers); part of a large early-allocation block rather than an individually-delegated ASN [Confirmed] — ARIN RDAP autnum/423

Contacts

abuse disa.columbus.ns.mbx.arin-registrations@mail.mil (DISA Columbus); registrant address 501 East Moore Dr, Bldg 884 Rm 1100, Gunther Annex, Maxwell AFB, AL 36114, US [Confirmed for abuse via RIPEstat; Confirmed for address via ARIN RDAP]

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-02 — not in Spamhaus ASN-DROP (direct feed fetch), no NANOG-archive mentions, no BGP-hijack report naming AS423; clean, unrouted government block [Confirmed for Spamhaus; Likely for NANOG/hijack absence] — spamhaus.org/drop/asndrop.txt, ipinfo.io/AS423

Network & routing

Network type

U.S. government / military network block (DoD / Air Force); AFCONC-BLOCK1-AS is a consolidated Air Force block, not a commercial ISP, content, or transit network [Confirmed] — ARIN RDAP, wpafb.af.mil office-supports-AF-network

Size

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

Routing/peering

NOT announced — 0 RIS peers seeing it (0/324 v4, 0/320 v6); CAIDA degree total 0 (customer 0, peer 0, provider 0); no upstreams or peers visible in any source [Confirmed]. No PeeringDB network record (both /api/net?asn=423 and /asn/423 → HTTP 404); operator's PeeringDB org 20118 lists AS65/123/175/221/301, not AS423 — no published peering policy [Confirmed]

RPKI

not assessable — AS423 announces no prefixes, so there are no ROAs to validate; RIPEstat rpki-validation requires a specific announced prefix and none exists [Confirmed]

Notable usage

dormant/unrouted DoD-block ASN; no visible BGP activity as of the July 2026 snapshot (bgp.he.net shows 0 originated/announced prefixes and 0 observed peers) [Confirmed] — bgp.he.net/AS423

Related ASNs

AFCONC-BLOCK1-AS range AS379–AS508 (adjacent DoD-block entries include AS385, AS404, AS420–AS422) [Confirmed for block range per ARIN; Likely for the specific adjacent list per third-party DB]

Analyst note

Encountered as a dormant, unrouted ASN inside ARIN's block-level AFCONC-BLOCK1-AS registration (AS379–AS508). RIPEstat and CAIDA independently agree on zero announcements. No dedicated public operator website ties to this specific ASN. RDAP fetch timed out in the canonical harness (A1) but A2/A3 read the same ARIN autnum record directly; findings corroborated across angles.