AS326

AS326 is a legacy autonomous system number registered under ARIN to the United States Department of Defense (DoD). It is one member of the contiguous DoD ASN block named DNIC-ASBLK-00306-00371 — a single ARIN allocation spanning AS306 through AS371 that the DoD reserved in the earliest days of the registry. The block-level autnum carries an ARIN registration date of 1989-06-30, last changed 2025-09-12, and the registrant handle is USDDD (United States Department of Defense). Administration runs through DISA-Columbus (the Defense Information Systems Agency facility at Whitehall/Columbus, Ohio), and the DoD Network Information Center (DoD NIC) serves as the operational contact; the NOC/technical/abuse address is disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil. AS326 is a stub autonomous system — single-homed, no transit — that historically originated about 35 IPv4 prefixes (roughly 35,328 addresses) drawn from the DoD-reserved 55.0.0.0/8 space (55.189.x, 55.190.x, 55.224.x), with no IPv6. The critical triage point is that AS326 is not currently announcing: RIPEstat shows announced=false as of the 2026-06-28 query, and all historical prefixes carry route timelines ending 2026-06-26T16:00:00, indicating the ASN withdrew all routes around June 26, 2026. RIPEstat's RIS collectors first observed it routing on 2011-07-22, but the ASN itself predates that observation by decades. It shows only a single observed BGP neighbour, no PeeringDB entry, no published peering policy, and no RPKI ROAs that could be confirmed. No notable public abuse signal was found as of 2026-06-28 — CleanTalk reports a 0.00% spam rate, the brianhama bad-asn-list does not include it, and no BGP hijack, route-leak, or NANOG discussion was attributable to AS326 — consistent with a clean, closed military government network.

Operator

United States Department of Defense (DoD); ARIN registrant handle USDDD; administered via DISA-Columbus (Defense Information Systems Agency) [Confirmed] — ARIN RDAP autnum/326, bgp.he.net/AS326, bgp.tools/as/326

Country / RIR

US, ARIN [Confirmed] — ARIN RDAP autnum/326; RIPEstat abuse-contact-finder (authoritative_rir: arin)

Allocated

1989-06-30 (ARIN registry date for the block-level autnum, NOT an IEEE date — IEEE publishes no ASN registration dates); last changed 2025-09-12 [Confirmed] — ARIN RDAP autnum top-level events

AS name / block

DNIC-ASBLK-00306-00371 — a single ARIN block spanning AS306–AS371; AS326 falls within it (block handle AS306) [Confirmed] — ARIN RDAP autnum/326

Org status

U.S. federal government agency (Department of Defense); registrant USDDD; administrative contact DISA-Columbus, 300 North James Road, Whitehall, OH 43213; registrant address 3990 E. Broad Street, Columbus, OH 43218 [Confirmed] — ARIN RDAP autnum/326

Contacts

disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil (NOC/technical/abuse via MIL-HSTMST-ARIN); +1-844-347-2457 [Confirmed] — ARIN RDAP autnum/326, RIPEstat abuse-contact-finder

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-28 — CleanTalk 0.00% spam rate / 0 listed IPs; absent from the brianhama bad-asn-list; no Spamhaus DROP listing surfaced; no BGP hijack/route-leak/NANOG mention attributable to AS326

Network & routing

Network type

Government / Military — stub AS (single-homed, no transit); no IXP presence [Confirmed] — bgp.he.net/AS326, bgp.tools/as/326, ipinfo.io/AS326

Size

~35 IPv4 prefixes (~35,328 addresses) historically, all in DoD-reserved 55.0.0.0/8 space (55.189.x, 55.190.x, 55.224.x); 0 IPv6 prefixes [Confirmed] — bgp.he.net/AS326, RIPEstat announced-prefixes

Routing status

NOT currently announcing — announced=false as of 2026-06-28; all historical prefix timelines end 2026-06-26T16:00:00 (routes withdrawn ~2026-06-26). RIS first observed routing 2011-07-22; last seen 2026-06-26 [Confirmed] — RIPEstat routing-status / as-overview / announced-prefixes

Peering

1 observed BGP neighbour; no PeeringDB entry for AS326; no published peering policy (closed military network). bgp.tools/ipinfo report AS306 (also DoD) as the associated peer/upstream [Confirmed for single-neighbour count; Likely for AS306 as the specific upstream] — bgp.tools/as/326, ipinfo.io/AS326, RIPEstat routing-status

RPKI

not confirmable — RPKI validation requires a per-prefix query that was not run; bgp.he.net observed 0 RPKI-valid / 0 RPKI-invalid origins [Unknown for ROA presence; Likely none] — bgp.he.net/AS326

Notable usage

block DNIC-ASBLK-00306-00371 is a legacy early-Internet DoD allocation managed by the DoD NIC via DISA-Columbus; AS326's prefixes have historically been attributed to "Headquarters, USAISC" (U.S. Army Information Systems Command, inactivated 1996; functions transferred to U.S. Army Signal Command, then NETCOM)

[Likely] — bgp.he.net/AS326, en.wikipedia.org/wiki/Army_Network_Enterprise_Technology_Command

Related ASNs

AS306–AS371 (the rest of the DNIC-ASBLK-00306-00371 DoD block); AS306 is the observed associated peer/upstream [Confirmed for the block; Likely for AS306 as specific upstream]

Analyst note

Legacy DoD block-member ASN, currently dormant in routing (all routes withdrawn ~2026-06-26). WHOIS/RDAP resolves cleanly to the U.S. Department of Defense via DISA-Columbus. No abuse signal. The 2011-07-22 "first seen" is RIS observation, not original allocation.