AS381

AS381 is a legacy autonomous system number registered under ARIN to Air Force Systems Networking — a U.S. Department of Defense / United States Air Force network resource administered by the Defense Information Systems Agency (DISA). It is not an individually-registered ASN: ARIN serves it as part of the contiguous AFCONC-BLOCK1-AS block record (startAutnum 379, endAutnum 508, RDAP handle keyed to AS379), so every registry fact below is a block-level attribute inherited by AS381 rather than an AS381-specific allocation event. The ARIN registrant org (handle 7ESG) lists an address at 501 East Moore Dr., Bldg 884 Rm 1100, Gunter Annex, Maxwell AFB, AL 36114, while the abuse, administrative, and technical contact routes through DISA-Columbus (300 North James Road, Whitehall, OH 43213; disa.columbus.ns.mbx.arin-registrations@mail.mil). The low-number range marks this as one of the earliest ASN allocations, consistent with DoD/Air Force internal networking dating to the origins of ASN assignment. The key triage point for AS381 is that it is effectively dormant today: RIPEstat reports announced=false, zero IPv4 and zero IPv6 prefixes, and 0 of ~323 v4 / ~322 v6 RIS peers seeing it as of 2026-07-02, with zero upstreams, zero observed neighbours, and a singleton customer cone (the ASN itself, 0 prefixes, 0 addresses). It did carry routes historically, though: RIPEstat's routing-status records a first-seen announcement of 206.37.36.0/24 on 2007-11-07 and a last-seen announcement of 132.3.28.0/22 on 2021-12-14, after which it has not been observed. RDAP status remains "active," but BGP visibility shows no public routing announcements. CAIDA AS-rank and customer-cone data could not be retrieved (the source lookup timed out), so those remain Unknown rather than guessed. No PeeringDB network object exists for AS381 specifically. RPKI posture is not assessable — there are no active originations and therefore no ROAs. Community corroboration search (NANOG archives, Reddit, PeeringDB, bgp.he.net, RIPEstat) yielded no operator mentions, outages, or reputation signals — absence consistent with a clean, dormant military ASN whose restricted public visibility reflects operational-security policy rather than reputation. It mirrors the profile of its immediate sibling AS380 and other members of the AS379–AS508 DoD/Air Force block.

Operator

Air Force Systems Networking (U.S. DoD / U.S. Air Force; ARIN OrgId 7ESG; administered by DISA) [Confirmed] — ARIN RDAP (https://rdap.arin.net/registry/autnum/381)

Country / RIR

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

Allocated

1989-08-04 (ARIN registry date from the autnum TOP-LEVEL registration event for the AS379–AS508 block containing AS381, NOT an IEEE date — IEEE publishes no ASN registration dates; the nested entity/org events are block-level facts)

[Confirmed] — ARIN RDAP autnum top-level events (https://rdap.arin.net/registry/autnum/381)

Org status

active per ARIN RDAP; U.S. Air Force network resource administered by DISA (Gunter Annex, Maxwell AFB, AL; DISA-Columbus, OH) [Confirmed] — ARIN RDAP (https://rdap.arin.net/registry/autnum/381)

Contacts

abuse/admin/tech via DISA-Columbus — disa.columbus.ns.mbx.arin-registrations@mail.mil; registrant HQ 501 East Moore Dr., Bldg 884 Rm 1100, Gunter Annex, Maxwell AFB, AL 36114 [Confirmed] — ARIN RDAP (https://rdap.arin.net/registry/autnum/381)

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-02 — not in Spamhaus DROP/ASN-DROP, nor in NANOG archives, Reddit, or general web searches; dormant/unrouted network limits abuse surface. Community corroboration search yielded no operator mentions or reputation signals

Network & routing

Network type

U.S. government / military network (DoD, U.S. Air Force / AFNET); not a commercial ISP, hosting, or content network; AS381 is legacy/inactive [Confirmed] — ARIN RDAP; bgp.tools/as/381

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 (https://stat.ripe.net/AS381)

Routing/peering

NOT announced — 0/323 v4 and 0/322 v6 RIS peers seeing it; RIPEstat observed_neighbours 0; historical first-seen 206.37.36.0/24 (2007-11-07) and last-seen 132.3.28.0/22 (2021-12-14); no public peering policy published; no AS381-specific PeeringDB network object

[Confirmed] — RIPEstat routing-status (https://stat.ripe.net/AS381), peeringdb.com/org/20118

AS rank / customer cone

Unknown — CAIDA lookup timed out ("The operation was aborted due to timeout"); no meaningful cone expected given 0 current announcements [Unknown] — CAIDA (error)

RPKI

not assessable — AS381 announces no prefixes, so there are no ROAs to validate (RIPEstat rpki-validation requires a prefix; none applicable) [Unknown] — RIPEstat rpki-validation (skipped, no prefix)

Notable usage

part of a contiguous historical ASN block (AS379 through AS508) allocated to Air Force Systems Networking for DoD/Air Force internal networking since the earliest ASN allocations; no specific public-facing services documented [Likely] — bgp.tools/as/381, whois.ipip.net/AS381

Block/RDAP anomaly note

RDAP for AS381 returns the block-level record (handle AS379, startAutnum 379 / endAutnum 508); ARIN exposes no AS381-specific sub-record, so all registry dates/org data are the block's top-level facts applied to AS381 as a member [Confirmed] — ARIN RDAP (https://rdap.arin.net/registry/autnum/381)

Community corroboration (Angle A5 — NANOG, Reddit, monitoring)

MINIMAL. No discussions found in NANOG mailing list archives, PeeringDB, bgp.he.net, or Reddit networking communities. No documented outages or abuse reports. Network's absence from public forums reflects its non-public-facing, dormant nature and DoD operational-security posture, not reputation issues [Confirmed] — NANOG archives (https://archive.nanog.org/list/archives.html, https://seclists.org/nanog/); PeeringDB (https://www.peeringdb.com/); bgp.he.net; RIPEstat (https://stat.ripe.net/AS381)

Analyst note

Encountered as a dormant legacy military ASN registered to Air Force Systems Networking via DISA; RDAP status is "active" but no prefixes are visible in public routing. The absence of community/peering presence reflects deliberate DoD operational security, not a defunct or ill-reputed operator. Same block/profile as sibling AS380 and other members of the historical DoD/Air Force ASN allocation block. Clean, inactive ASN.