AS353

AS353 is a legacy autonomous system number registered under ARIN to the United States Department of Defense (DoD), administered operationally by the Defense Information Systems Agency (DISA) from its Columbus, Ohio facility. The number is one assignment within the contiguous DoD-controlled block DNIC-ASBLK-00306-00371 (AS306–AS371), whose RDAP record carries the parent handle AS306. Three independent angles (ARIN RDAP, RIPEstat, and bgp.he.net) agree on the holder and on the block context; the registration event on the ARIN autnum record dates the allocation to 1989-06-30, with the record last changed 2025-09-12. Operationally AS353 is a single-homed stub: it originates exactly one IPv4 prefix, 55.41.0.0/16 (65,536 addresses, labelled "Headquarters, USAISC" — U.S. Army Information Systems Command — in BGP records), no IPv6, and its only observed neighbour and upstream is the sibling DoD AS306. RIPEstat's as-overview reported announced: false at the 2026-06-28 query snapshot, but routing-status and announced-prefixes show the prefix was actively seen in RIS as recently as 2026-06-26 (first seen 2016-10-28), with 324 of 326 v4 RIS peers seeing it at last sighting. The prefix carries no RPKI ROAs (0 valid / 0 invalid per bgp.he.net), and bgp.he.net's bogon heuristic flags the 55/8 space (a reserved DoD allocation). On the security side, no notable public abuse signal was found as of 2026-06-28: AS353 is absent from the Spamhaus ASN-DROP list and the brianhama bad-ASN community blocklist, and no AS353-specific BGP incidents surfaced (the well-known January 2021 DoD BGP pilot involved AS8003, not AS353). CAIDA AS Rank was unavailable (HTTP 502), so customer-cone and AS-rank metrics are recorded as Unknown.

Operator

United States Department of Defense (DoD), administered by DISA Columbus (DoD NIC); ARIN org handle USDDD [Confirmed] — ARIN RDAP autnum/353, RIPEstat as-overview, bgp.he.net/AS353

Country / RIR

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

Allocated

1989-06-30 (ARIN registry date from the autnum top-level registration event; NOT an IEEE date — IEEE publishes no ASN dates); last changed 2025-09-12 [Confirmed] — ARIN RDAP autnum top-level events (handle AS306, block DNIC-ASBLK-00306-00371)

Org status

active U.S. federal government entity; operational contacts at DISA Columbus, 300 North James Road, Whitehall, OH 43213 [Confirmed] — ARIN RDAP, ipinfo.io/AS353

Contacts

disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil; +1-844-347-2457 ext 2 (POC handle MIL-HSTMST-ARIN) [Confirmed] — RIPEstat abuse-contact-finder, ARIN RDAP

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-28 — absent from Spamhaus ASN-DROP and the brianhama bad-asn-list; no AS353-specific BGP hijack/leak incidents (the Jan-2021 DoD BGP pilot was AS8003, not AS353); 0 IPs responded to public ICMP scans [Likely] — spamhaus.org/drop/asndrop.json, raw.githubusercontent.com/brianhama/bad-asn-list, ipinfo.io/AS353, kentik.com/blog/the-mystery-of-as8003

Network & routing

Network type

government stub AS — single-homed, provides no transit; originates 1 IPv4 prefix, no IPv6; sole upstream/peer is AS306 (DoD) [Confirmed] — bgp.he.net/AS353, ipinfo.io/AS353, bgp.tools/as/353

Size

1 IPv4 prefix (55.41.0.0/16 = 65,536 addresses); 0 IPv6 prefixes [Confirmed] — RIPEstat announced-prefixes, bgp.he.net/AS353

Routing/peering

as-overview reported announced:false at the 2026-06-28 snapshot, but RIS routing-status shows 55.41.0.0/16 last seen 2026-06-26 (first seen 2016-10-28), 324/326 v4 RIS peers, 0/324 v6; 1 observed neighbour. No public peering policy — DoD/DNIC restricts peering details; sole peer/upstream AS306

[Confirmed] — RIPEstat routing-status / announced-prefixes, bgp.he.net/AS353, peeringdb.com/org/17705

RPKI

no ROAs covering announcements — bgp.he.net shows 0 RPKI-valid and 0 RPKI-invalid origins; RIPEstat rpki-validation was skipped this run (no --prefix supplied) [Likely] — bgp.he.net/AS353

Notable usage

originates 55.41.0.0/16, labelled "Headquarters, USAISC" (U.S. Army Information Systems Command) in BGP records; bgp.he.net flags the 55/8 reserved DoD space under its bogon heuristic [Confirmed] — bgp.he.net/AS353, ipinfo.io/AS353

Related ASNs

AS306 (DoD; block parent handle and sole observed neighbour/upstream); AS353 is an individual assignment within DNIC-ASBLK-00306-00371 (AS306–AS371) [Confirmed] — ARIN RDAP autnum/353

Analyst note

A5 (community angle) misidentified AS353 as the Internet Software Consortium / ISC (BIND/DHCP) — that attribution is incorrect and was discarded. The correct holder, corroborated by four angles (RDAP, RIPEstat, bgp.he.net, ipinfo), is the U.S. Department of Defense. CAIDA was unavailable (HTTP 502), so customer-cone and AS-rank are Unknown/null.