AS361

AS361 is a legacy autonomous system number registered under ARIN to the United States Department of Defense (DoD). It does not stand alone in the registry: it falls inside the ARIN-allocated block DNIC-ASBLK-00306-00371 (spanning AS306 through AS371), whose registrant handle is USDDD. Day-to-day registration and administration of this DNIC (DoD Network Information Center) block is handled by the Defense Information Systems Agency (DISA), specifically its DISA-Columbus team in Whitehall, Ohio — the RDAP contact vCards list a Columbus/Whitehall postal address and a @mail.mil hostmaster mailbox. The block-level ARIN RDAP autnum object carries a top-level registration event of 1989-06-30 and a last-changed event of 2025-09-12, and its status is Active; this registration date is the first-party RIR allocated_date and is recorded as such. The network is a government/military segment rather than a commercial or transit provider: third-party aggregators classify it as a stub AS (single-homed, no downstream customers) whose single upstream is AS306, itself a DoD ASN. RIPEstat confirms the ASN is announced, with 14 IPv4 prefixes (393,216 addresses) drawn from the 55.0.0.0/8 legacy DoD space (for example 55.6.0.0/16, 55.59.0.0/16, 55.62.0.0/16, 55.63.0.0/16, 55.96.0.0/16, 55.97.0.0/16) plus 1 IPv6 prefix (2608:10a:1400::/40); the earliest-observed announcement is 55.6.0.0/16 under origin AS361 dating to 2008-07-30. CAIDA ranks the ASN 12654 by AS rank and places its customer cone at a single ASN (itself) covering the same 14 prefixes / 393,216 addresses, with an ASN-degree of 1 provider, 0 peers, 0 customers — consistent with a single-homed stub. No dedicated public operator website exists for AS361 itself — it is an internal DoD address block — with DISA (disa.mil) the plausible parent-organization presence but unverified as a page about this ASN. No notable public abuse, spam-source, BGP-hijack, or route-leak signal specifically attributed to AS361 was found as of 2026-07-01 across Spamhaus, CleanTalk, NANOG/seclists archives, and general threat-intel sources — a sourced null consistent with a closed, restricted government network.

Operator

United States Department of Defense (DoD); administered by DISA (Defense Information Systems Agency), DISA-Columbus, Whitehall/Columbus, OH [Confirmed] — ARIN RDAP autnum (registrant handle USDDD), https://rdap.arin.net/registry/autnum/361

Country / RIR

US, ARIN [Confirmed] — ARIN RDAP autnum, https://rdap.arin.net/registry/autnum/361

Allocated

1989-06-30 (ARIN RDAP autnum TOP-LEVEL registration event for block DNIC-ASBLK-00306-00371; a first-party RIR registry fact, NOT an IEEE date — IEEE publishes no ASN dates); last changed 2025-09-12 [Confirmed] — ARIN RDAP autnum top-level events[], https://rdap.arin.net/registry/autnum/361

Block context

AS361 sits within DNIC-ASBLK-00306-00371 (AS306–AS371); no narrower per-ASN registration event distinct from the block-level record was returned [Confirmed] — ARIN RDAP, RIPEstat as-overview (holder "DNIC-ASBLK-00306-00371 - United States Department of Defense (DoD)")

Org status

Active [Confirmed] — ARIN RDAP autnum status "active", https://rdap.arin.net/registry/autnum/361

Website

no dedicated AS361 operator site (internal DoD block); disa.mil is the plausible parent-org presence but unverified as an AS361-specific page [Unknown] — https://rdap.arin.net/registry/autnum/361

IANA reference

none found; left blank per no-fabrication rule [Unknown]

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-01 — no Spamhaus/CleanTalk listing, NANOG/seclists thread, or hijack/leak writeup naming AS361; Scamalytics publishes a 0/100 fraud-risk score for the "DoD Network Information Center" ISP label (org-level, not AS361-exclusive)

Network & routing

Network type

government/military stub AS (single-homed, non-transit); part of the Defense Information Systems Network (DISN) [Likely] — IPinfo classification, https://ipinfo.io/AS361

Size / prefixes

announced=true; 14 IPv4 prefixes / 393,216 addresses and 1 IPv6 prefix (2608:10a:1400::/40), including 55.6.0.0/16, 55.59.0.0/16, 55.62.0.0/16, 55.63.0.0/16, 55.96.0.0/16, 55.97.0.0/16; first observed announcement 55.6.0.0/16 under AS361 at 2008-07-30 [Confirmed] — RIPEstat routing-status + announced-prefixes, https://stat.ripe.net/data/routing-status/data.json?resource=361, https://stat.ripe.net/data/announced-prefixes/data.json?resource=361

Routing/peering

reported upstream AS306 (DoD); RIPEstat observed_neighbours=1; CAIDA asnDegree provider=1, peer=0, customer=0; no PeeringDB entry; DISN interconnects with commercial networks only through DoD CIO-approved gateways (enterprise-level DISN policy, not confirmed AS361-specific) [Confirmed/Likely] — https://stat.ripe.net/data/routing-status/data.json?resource=361, https://api.asrank.caida.org/v2/restful/asns/361, DISN Connection Process Guide (disa.mil)

CAIDA AS rank / cone

as_rank=12654; customer cone = 1 ASN, 14 prefixes, 393,216 addresses [Confirmed] — CAIDA ASRank, https://api.asrank.caida.org/v2/restful/asns/361

RPKI

not assessed — RIPEstat rpki-validation was skipped (requires a --prefix); no ROA/RPKI validity data for AS361 as a whole from this pass [Unknown]

Geo footprint

registrant/administrative address is Columbus/Whitehall, Ohio, US (DISA-Columbus, 300 North James Road, Whitehall, OH 43213; org 3990 E. Broad Street, Columbus, OH 43218) — registration address only, not a verified announcement footprint

[Likely] — ARIN RDAP entity vCards, https://rdap.arin.net/registry/autnum/361

Notable usage

associated domain observed by IPinfo is mail.mil; large 55.0.0.0/8-derived DoD netblocks announced under this operator grouping [Likely] — https://ipinfo.io/AS361

Analyst note

A block-level DoD DNIC ASN; the allocated_date (1989-06-30) is the block autnum's top-level registration event and was deliberately taken over decoy entity-level dates (contacts registered 1993-05-26 / 2009-06-24; org 2007-01-12). Routing metrics (prefix counts, address estimate, AS rank, customer cone, ASN degree) are sourced from the untruncated RIPEstat routing-status and CAIDA ASRank endpoints.