AS355

AS355 is a legacy autonomous system number registered under ARIN to the United States Department of Defense (DoD). It does not resolve to a distinct per-ASN record: ARIN's RDAP autnum lookup for 355 returns the block-level object handle AS306, name DNIC-ASBLK-00306-00371, spanning ASNs 306 through 371 — a bulk DoD Network Information Center (DNIC) allocation. ARIN returns this same block object for any number in the 306–371 range, so no service branch, base, or DISA-by-name operator is distinguishable from the registry for AS355 alone; the confirmable operator identity is simply "U.S. Department of Defense." The block's ARIN top-level registration event is dated 1989-06-30 (last changed 2025-09-12), an early-Internet-era allocation. Unlike its dormant legacy siblings, AS355 is actively announcing: RIPEstat and CAIDA agree it originates three IPv4 prefixes totaling 65,536 addresses (55.46.0.0/16 plus its two /17 sub-announcements) and one IPv6 prefix, 2608:18a:5200::/40 (256 /48s). The /16 was first observed in RIPE RIS BGP data on 2009-05-08 and was still seen on 2026-07-01, with broad visibility (323/325 v4 RIS peers, 323/323 v6). CAIDA classifies it as a stub AS: total degree 1, zero customers, zero peers, and a single upstream provider that CAIDA and RIPEstat both count but do not name. It is a CAIDA clique member with an AS rank of 14,259 and a singleton customer cone. RPKI posture was not assessed (the RIPEstat check requires a per-prefix parameter that was not supplied). No notable public abuse signal was found for AS355 as of 2026-07-01 across AbuseIPDB, Spamhaus, bgp.tools, and NANOG archives — consistent with a restricted internal military network (IPinfo reports zero hosted domains and no ping responses). Note: the widely covered 2021 announcement of ~175M dark DoD IPv4 addresses was AS8003 (GRS-DoD), a different ASN, and is not attributable to AS355.

Operator

United States Department of Defense (DoD), managed via the DoD Network Information Center (DNIC); block administered by DISA-Columbus (Columbus, OH) [Confirmed] — ARIN RDAP, ipinfo.io/AS355, bgp.tools/as/355

Country / RIR

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

Allocated

1989-06-30 (ARIN RDAP block-level registration event for DNIC-ASBLK-00306-00371; a first-party RIR registry fact, NOT an IEEE/OUI database artifact); last changed 2025-09-12 [Confirmed] — ARIN RDAP autnum top-level events; corroborated by ipinfo.io and bgp.tools ("registered June 30, 1989")

Contacts

abuse disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil; registrant contact 300 North James Road, Whitehall, OH 43213 (DISA-Columbus) [Confirmed for abuse/RIR via RIPEstat + RDAP]

Org status

active; ARIN block record status "Active", registration 1989-06-30, last changed 2025-09-12 [Confirmed] — ARIN RDAP

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-01 — not in AbuseIPDB, Spamhaus, bgp.tools reputation, or NANOG archives, for AS355 or its prefixes; absence of evidence across public sources, not an exhaustive proprietary-feed audit

Network & routing

Network type

government/military stub AS (single-homed, provides no transit) [Confirmed] — ipinfo.io/AS355, bgp.tools/as/355

Size

3 IPv4 prefixes / 65,536 addresses (55.46.0.0/16, 55.46.0.0/17, 55.46.128.0/17 — the two /17s sub-announce the /16) and 1 IPv6 prefix 2608:18a:5200::/40 (256 /48s) [Confirmed] — RIPEstat announced-prefixes / routing-status, CAIDA AS Rank

Routing/peering

announced — RIS visibility 323/325 v4 and 323/323 v6; first seen 2009-05-08, last seen 2026-07-01 (55.46.0.0/16 origin 355); CAIDA degree total 1 (customer 0, peer 0, provider 1); single upstream provider not named by CAIDA/RIPEstat; RIPEstat observed_neighbours 1 [Confirmed]. Upstream AS306 (also DoD) reported by bgp.tools

[Likely] — RIPEstat routing-status, CAIDA AS Rank, bgp.tools/as/355

Peering policy

Unknown — no PeeringDB net entry exists for AS355 and no official peering-policy page for the DNIC block was located; DISA's general DISN connection guidance does not reference AS355 by number [Unknown] — peeringdb.com (no net record for 355)

RPKI

Unknown — not evaluated; the RIPEstat rpki-validation query requires a per-prefix parameter (e.g. --prefix 55.46.0.0/16) that was not supplied, so the field was skipped, not queried-and-empty [Unknown] — RIPEstat rpki-validation

CAIDA rank

AS rank 14,259; clique member (reachable via a Tier-1/DoD transit arrangement despite low degree); customer cone = singleton (1 ASN, 3 prefixes, 65,536 addresses) [Confirmed] — asrank.caida.org/api/v2/restful/asns/355

Geo footprint

US; CAIDA coarse coordinate ~33.97N, −81.18W (Columbia, SC area) — an inference-based estimate that does not match the RDAP registrant contact address (300 North James Road, Whitehall, OH 43213, DISA-Columbus), so treat as approximate [Likely] — CAIDA AS Rank, ARIN RDAP

Notable usage

restricted/internal military network; IPinfo reports 0 hosted domains and no ICMP ping responses, consistent with non-public-facing use [Likely] — ipinfo.io/AS355

Registry record scope

block-level autnum (handle AS306, startAutnum 306, endAutnum 371) — ARIN returns this same object for any ASN in the DoD 306–371 range; there is no more granular per-ASN date for AS355 [Confirmed] — ARIN RDAP

Related-but-distinct

the 2021 announcement of ~175M dark DoD IPv4 space was AS8003 (GRS-DoD), a Defense Digital Service pilot — a DIFFERENT ASN, not attributable to AS355 [Confirmed] — kentik.com/blog/the-mystery-of-as8003, theregister.com (2021-04-26)

Analyst note

encountered as an actively-announcing DoD stub ASN whose RDAP resolves only to the block-level DNIC record (AS306–AS371); operator confirmed as DoD, but any DISA-specific website/peering attribution is Unknown, not fabricated. The 1989-06-30 date is the block's allocation and should be published with that block-level caveat so it is not misread as a per-ASN-only event.