AS370

AS370 is a legacy autonomous system number administered by ARIN and registered to the United States Department of Defense (DoD), organization handle USDDD. It is not an individually branded network: ARIN returns a single block-level autnum object, DNIC-ASBLK-00306-00371 (handle AS306, spanning AS306 through AS371), for every number in this Defense Network Information Center (DNIC) range, and AS370 is one number inside it. Operational administration runs through the Defense Information Systems Agency (DISA) / DoD Network Information Center at DISA-Columbus, Whitehall, Ohio. Unlike the dormant legacy ASNs common in old registry blocks, AS370 is actively routed: RIPEstat and bgp.he.net agree it announces roughly 137 IPv4 prefixes (about 262,144 addresses, largely inside 55.0.0.0/8 space such as 55.54.0.0/16, 55.79.0.0/16, and 55.93.0.0/16) plus one IPv6 prefix, 2608:10a:6000::/40. CAIDA classifies it as a stub network: customer cone of a single ASN, no downstream customers, and a single observed upstream — AS306, itself a DoD DNIC-block ASN. RPKI coverage appears absent (bgp.he.net shows no ROAs), and no public abuse, hijack, or NANOG-thread signal naming AS370 was found as of 2026-07-02 — an honest absence-of-evidence result for a DoD-allocated ASN rather than a verified-clean attestation. The block-level ARIN registration event is 1989-06-30, with the record last changed 2025-09-12.

Operator / registrant

United States Department of Defense (DoD), ARIN org handle USDDD; administered by DISA / DoD Network Information Center (DNIC), DISA-Columbus, Whitehall, OH [Confirmed] — https://rdap.arin.net/registry/autnum/370

Country / RIR

US, ARIN (American Registry for Internet Numbers) [Confirmed] — https://rdap.arin.net/registry/autnum/370

Allocated

1989-06-30 (ARIN RDAP autnum top-level registration event for the DNIC-ASBLK-00306-00371 object that contains AS370 — a first-party RIR registry fact, recorded per project rule; it is a block-level date, ARIN exposes no separate per-ASN event inside a DNIC block); last changed 2025-09-12 [Confirmed for the registry event; the block-vs-per-number scope is noted] — https://rdap.arin.net/registry/autnum/370

Org status

Active (ARIN RDAP autnum status = "active") [Confirmed] — https://rdap.arin.net/registry/autnum/370

Contacts

NOC/abuse/technical group "Network DoD" (handle MIL-HSTMST-ARIN), disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil, +1-844-347-2457 ext2, DISA-Columbus, 300 North James Road, Whitehall, OH 43213; registrant address 3990 E. Broad Street, Columbus, OH 43218

[Confirmed] — https://rdap.arin.net/registry/autnum/370

Security / abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-02 across Spamhaus, general threat-intel, and NANOG archive web searches; live routing status independently confirmed via RIPEstat/bgp.he.net. Absence of evidence, not a verified-clean attestation

Network & routing

Network type

government / military (DoD/NIPRNet numbering); third-party BGP tooling classifies it as a stub AS (single-homed, no transit provided) [Confirmed for org; Likely for stub classification] — https://ipinfo.io/AS370, https://api.asrank.caida.org/v2/restful/asns/370

Size / announcements

~137 IPv4 prefixes, ~262,144 IPv4 addresses (/16-equivalent; e.g. 55.54.0.0/16, 55.79.0.0/16, 55.93.0.0/16), plus one IPv6 prefix 2608:10a:6000::/40 [Confirmed] — https://stat.ripe.net/AS370, https://bgp.he.net/AS370

Routing / peering

announced and highly visible (RIS v4 321/323, v6 322/322 peers); CAIDA asnDegree total 1 (provider 1, customer 0, peer 0); sole observed upstream is AS306 (also a DoD DNIC-block ASN); no settlement-free peers observed

[Confirmed] — https://stat.ripe.net/AS370, https://api.asrank.caida.org/v2/restful/asns/370, https://bgp.he.net/AS370

AS rank / cone

CAIDA global AS rank 12740; customer cone = 1 ASN, 130 prefixes, 262,144 addresses (stub/leaf) [Confirmed] — https://api.asrank.caida.org/v2/restful/asns/370

RPKI

no ROAs found; effectively unvalidated for AS370's announcements as of fetch date [Likely] — https://bgp.he.net/AS370

Peering policy

not publicly published for AS370 specifically; no PeeringDB net object located. DISA/NIPRNet security posture (DoD Router Security Requirements Guide) generally forbids DISN perimeter routers peering with alternate/commercial gateways — contextual, not AS370-specific policy

[Likely] — https://www.peeringdb.com/org/17705, https://cyber.trackr.live/stig/Router_Security_Requirements_Guide/5/1

Notable usage

DoD/NIPRNet address space in the DNIC-ASBLK-00306-00371 range administered by DISA-Columbus; bgp.he.net labels some subnets "Headquarters, USAISC" (U.S. Army Information Systems Command). No first-party DISA statement describing AS370's specific purpose was found

[Likely] — https://bgp.he.net/AS370, https://rdap.arin.net/registry/autnum/370

Related ASNs

AS306 (AS370's sole upstream; same DoD DNIC block AS306–AS371) [Confirmed] — https://api.asrank.caida.org/v2/restful/asns/370, https://rdap.arin.net/registry/autnum/370

Assignment class

allocated (legacy DNIC block; DNIC-ASBLK-00306-00371, startAutnum 306, endAutnum 371) [Confirmed] — https://rdap.arin.net/registry/autnum/370

Analyst note

ARIN returns a block-level autnum (handle AS306, AS306–AS371) for the AS370 query; there is no per-ASN RDAP record inside the DNIC block. The 1989-06-30 top-level registration event is recorded as allocated_date per project rule (a first-party RIR fact), with the block-level scope disclosed rather than fabricating a per-number date.