AS350

AS350 is a legacy autonomous system number registered under ARIN to the United States Department of Defense (DoD), administered by the Defense Information Systems Agency (DISA) out of Columbus, Ohio. It is not a standalone registration: ARIN issues a single RDAP autnum record (handle AS306) covering the contiguous block DNIC-ASBLK-00306-00371 (AS306 through AS371), and AS350 falls inside that block under the DoD registrant org handle USDDD. The triage point for AS350 is that it is a tightly held government stub AS that was, until very recently, announcing DoD address space and is now quiet. As of 2026-06-28 RIPEstat reports announced: false, but the announced-prefixes endpoint shows four IPv4 prefixes (55.4.0.0/16, 55.30.0.0/16, 55.4.192.0/18, 55.30.192.0/18) and one IPv6 prefix (2608:18a:3400::/40) active as recently as 2026-06-26T16:00:00, then withdrawn — these sit inside the historic 55.0.0.0/8 MILNET/DoD allocation. The AS has a single observed BGP neighbour (AS306, also DoD/DISA), consistent with a closed internal government routing topology with no public transit and no public IX peering. RPKI posture is not assessable at query time because no prefix was active to validate. No notable public abuse signal was found as of 2026-06-28 — absent from Spamhaus ASN-DROP, a 0% CleanTalk spam rate, nothing in NANOG archives or community blocklists — consistent with a clean, long-established U.S. government stub ASN.

Operator

United States Department of Defense (DoD); network operations managed by DISA-Columbus (ARIN org handle USDDD) [Confirmed] — ARIN RDAP autnum/350, bgp.tools/as/350

Country / RIR

US, ARIN [Confirmed] — ARIN RDAP autnum/350; RIPEstat abuse-contact-finder (authoritative_rir: arin)

Allocated

1989-06-30 (ARIN autnum top-level registration event for block DNIC-ASBLK-00306-00371 covering AS350 — a first-party RIR registry fact, NOT an IEEE date); last changed 2025-09-12 [Confirmed] — ARIN RDAP autnum top-level events

Org status

active U.S. federal agency (Department of Defense); NOC contact disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil, +1-844-347-2457; address DISA-Columbus, 300 North James Road, Whitehall, OH 43213; registrant org address 3990 E. Broad Street, Columbus, OH 43218 [Confirmed] — ARIN RDAP autnum/350

Website

nic.mil is the historical DoD NIC domain (now archived); DISA manages operations via disa.mil; no operator-published site specific to AS350 [Likely] — ip2location.com/as350, archived nic.mil

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-28 — not in Spamhaus ASN-DROP (425-record list), 0% CleanTalk spam rate, nothing in NANOG archives or community blocklists; CIDR Report notes only a benign aggregation inefficiency (two more-specific /18s overlap their parent /16s); an unconfirmed bgp.he.net "announces bogons" flag could not be corroborated in the live bogon reports [Confirmed for no-signal; Likely for the routing note] — spamhaus.org/drop/asndrop.json, cleantalk.org/blacklists/asn350, cidr-report.org

Network & routing

Network type

U.S. federal government / military network; stub AS (single-homed, no transit provided) [Confirmed] — ipinfo.io/AS350, bgp.tools/as/350

Routing/peering

NOT currently announced (RIPEstat announced: false as of 2026-06-28); four IPv4 prefixes (55.4.0.0/16, 55.30.0.0/16, 55.4.192.0/18, 55.30.192.0/18) and one IPv6 prefix (2608:18a:3400::/40) were active through 2026-06-26 then withdrawn; routing first seen 2011-07-22, last seen 2026-06-26; one observed neighbour

[Confirmed] — RIPEstat as-overview / announced-prefixes / routing-status

Upstreams / peers

sole observed BGP peer is AS306 (also DoD/DISA) for both IPv4 and IPv6; no public peering policy published; no public IX peering [Likely] — bgp.he.net/AS350, bgp.tools/as/350

RPKI

not assessable — no active prefix to validate against at query time [Unknown] — RIPEstat rpki-validation (skipped, no prefix)

Notable usage

prefixes sit within the historic 55.0.0.0/8 MILNET/DoD allocation; bgp.he.net attributes the 55.4/55.30 space to USAISC (U.S. Army Information Systems Command) HQ; part of a broader DoD ASN portfolio (20+ ASNs under org handle USDDD) [Likely] — bgp.he.net/AS350, peeringdb.com/org/17705

Related ASNs

AS306 (sole observed peer, also DoD/DISA); the DNIC-ASBLK-00306-00371 block spans AS306–AS371; DoD operates additional ASNs under handle USDDD [Confirmed for AS306 / block span; Likely for the broader portfolio]

RDAP block name

DNIC-ASBLK-00306-00371 (AS306–AS371; AS350 falls within this DoD-registered block) [Confirmed] — ARIN RDAP autnum/350

Analyst note

Encountered as a quiet DoD stub ASN inside a contiguous ARIN-registered block. The autnum record is keyed to the block (handle AS306); the 1989-06-30 top-level registration event is the authoritative allocation date applicable to AS350. Clean, government-controlled ASN; recently withdrew its announcements.