AS505

AS505 is a legacy autonomous system number administered by ARIN as part of a block registration spanning AS379 through AS508, held under the handle AS379 and named AFCONC-BLOCK1-AS. The registrant organization is "Air Force Systems Networking" (ARIN entity 7ESG), a U.S. Air Force/Department of Defense entity, with administrative, technical, and abuse contact duties assigned to a DISA (Defense Information Systems Agency) group based in Columbus, Ohio. Because ARIN treats AS379–AS508 as a single sequential military block rather than issuing per-ASN records, the registry dates returned for "AS505" are the block's own top-level registration events, not an AS505-specific allocation record — this is standard behavior for legacy DoD blocks and is recorded here rather than treated as an anomaly. AS505 itself shows no live routing activity: RIPEstat, CAIDA ASRank, and Hurricane Electric's BGP Toolkit independently agree it announces zero IPv4 and zero IPv6 prefixes, has zero observed BGP peers or upstreams, and sits in CAIDA's ranking at position 79,459 with a singleton customer cone. No PeeringDB record, operator website, or public peering policy exists for the ASN. A direct check of Spamhaus's ASN-DROP list found no listing, and broader searches surfaced no abuse reporting tied to AS505 — consistent with an unrouted, dormant government allocation with no active attack surface.

Operator

Air Force Systems Networking (ARIN entity 7ESG; U.S. Air Force / DoD), admin/tech/abuse handled by DISA-Columbus (REGIS10-ARIN) [Confirmed] — https://rdap.arin.net/registry/autnum/505

Country / RIR

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

Allocated

1989-08-04 (ARIN RDAP top-level autnum registration event for block AS379–AS508, handle AS379, name AFCONC-BLOCK1-AS); last changed 2008-06-06 [Confirmed] — https://rdap.arin.net/registry/autnum/505

Org status

Active per ARIN registry status; registered address 501 East Moore Dr. Bldg 884 Rm 1100, Gunther Annex, Maxwell AFB, AL 36114, US [Confirmed] — https://rdap.arin.net/registry/autnum/505

Website

Unknown — no dedicated operator website found for AS505 or the AFCONC-BLOCK1-AS block; DISA's general public site (disa.mil) has no page identifying this ASN specifically, so not asserted as the operator site [Unknown]

Security/abuse context (NEUTRAL, DATED)

No listing on Spamhaus ASN-DROP as of 2026-07-10; broader search across AbuseIPDB, abuse.ch, and NANOG archives surfaced no abuse reports tied to AS505; consistent with an unrouted ASN with no active attack surface [Confirmed for Spamhaus check; Likely for broader absence-of-reporting claim] — https://www.spamhaus.org/drop/asndrop.txt

Network & routing

Network type

Not publicly documented in operator terms; registry classification only — a legacy ARIN direct allocation to a U.S. military/DoD entity, no self-described network-type statement found [Unknown] — https://rdap.arin.net/registry/autnum/505

Size / routing

NOT announced — 0 IPv4 and 0 IPv6 prefixes; 0 RIS peers seeing it (0/327 v4, 0/321 v6); 0 observed neighbours [Confirmed] — RIPEstat routing-status, https://bgp.he.net/AS505

Peering

No PeeringDB network record exists for AS505 (API query for asn=505 returns empty/404); no public peering policy found on any DISA or Air Force domain [Confirmed absence] — peeringdb.com

RPKI

Not assessable — zero announced prefixes, so there are no ROAs to validate; bgp.he.net shows 0 RPKI-valid and 0 RPKI-invalid routes [Confirmed] — https://bgp.he.net/AS505

CAIDA AS rank

79,459; customer cone = singleton (1 ASN, 0 prefixes, 0 addresses); asnDegree total/customer/peer/provider all 0; not a clique member [Confirmed] — https://asrank.caida.org/asns/505

Notable usage

Unknown from operator-official sources — no operator page describing AS505's specific usage or purpose was found beyond its DoD/Air Force registry classification; third-party BGP aggregators list the same block name but are not operator-official [Unknown]

Block membership note

AS505 is not individually registered in ARIN's database; ARIN groups AS379 through AS508 into one block record under handle AS379. The dates above are the block's top-level events, applied to every member ASN including AS505 — expected ARIN behavior for legacy sequential military blocks, not an error

[Confirmed] — https://rdap.arin.net/registry/autnum/505

Analyst note

Encountered as a dormant legacy DoD/Air Force ASN inside a sequential military block (AS379–AS508); no independent routing activity, PeeringDB record, or public abuse signal found.