AS170

AS170 is one of the oldest Autonomous System Numbers on the internet, registered through ARIN on 1988-04-12 and held by the United States Department of Defense (DoD). It is administered by the Defense Information Systems Agency (DISA) through the DoD Network Information Center (DNIC), with the registrant org listed as "United States Department of Defense (DoD)" (ARIN OrgId USDDD) at 3990 E. Broad Street, Columbus, OH. The ASN name DNIC-AS-00170 follows the DoD's long-standing DNIC naming convention used across its large estate of legacy autonomous systems. Operationally, AS170 is currently dormant: it announces no prefixes in the global BGP routing table (0 IPv4, 0 IPv6), and RIPEstat shows 0 of 327 IPv4 RIS peers and 0 of 323 IPv6 RIS peers seeing it as of 2026-06-17. Its single historically originated route, 215.1.4.0/24 — a /24 inside the DoD-held 215.0.0.0/8 legacy block — was first observed in BGP on 2013-02-28 and last seen on 2026-04-17 before being withdrawn; bgp.he.net flags it as a bogon, consistent with a non-globally-routed DoD block. The only historical BGP neighbor recorded is the DoD-sibling AS27066, consistent with closed intra-DoD arrangements rather than public IXP peering. No PeeringDB entry exists for AS170, so its peering policy is not publicly documented. No notable public abuse signal was found as of 2026-06-17: AS170 is absent from the Spamhaus ASN-DROP list and presents no reachable attack surface while withdrawn from routing. Because no IP space is currently routed under it, AS170 reads as a dormant or retired number within the DoD's large legacy ASN estate, managed by DISA-Columbus.

Operator

United States Department of Defense (DoD), administered by DISA via the DoD Network Information Center (DNIC); ARIN OrgId USDDD, Columbus, OH [Confirmed] — ARIN RDAP (https://rdap.arin.net/registry/autnum/170)

Country / RIR

US, ARIN [Confirmed] — ARIN RDAP

Allocated

ARIN AS170 RegDate 1988-04-12 (a database record artifact from ARIN, NOT an IEEE registration date — IEEE publishes none); autnum last changed 2025-09-12 [Confirmed for the shown dates] — ARIN RDAP

Org status

active US Federal Government combat support agency. DISA (formerly Defense Communications Agency, est. 1960; renamed DISA 1991) is a DoD combat support agency headquartered at Fort George G. Meade, Maryland [Confirmed] — en.wikipedia.org/wiki/Defense_Information_Systems_Agency, usa.gov

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-17; absent from Spamhaus ASN-DROP; no reachable IP space while withdrawn; the 2021 DoD BGP pilot that drew NANOG attention was AS8003/GRSCORP, a separate ASN

Network & routing

Network type

US Federal Government / Military; legacy ASN currently not in the global routing table [Confirmed] — bgp.tools/as/170, bgp.he.net/AS170

Size

not announcing — 0 IPv4 prefixes / 0 IPv6 prefixes / 0 addresses originated as of 2026-06-17 [Confirmed] — RIPEstat routing-status (https://stat.ripe.net/data/routing-status/data.json?resource=170), bgp.he.net/AS170

Routing/peering

withdrawn from global table; 0/327 IPv4 and 0/323 IPv6 RIS peers see it [Confirmed]; only historical neighbor is DoD-sibling AS27066 [Likely] — RIPEstat routing-status, bgp.he.net/AS170

Notable usage

one of the oldest allocated ASNs (1988-04-12); part of the DoD DNIC legacy estate; historically originated 215.1.4.0/24 from the DoD 215.0.0.0/8 block (last seen 2026-04-17, flagged bogon by bgp.he.net) — RIPEstat routing-status, bgp.he.net/AS170

Related ASNs

AS27066 (United States Department of Defense; historical neighbor); DoD operates many other DNIC-block ASNs [Confirmed for AS27066] — bgp.he.net/AS170

Analyst note

Encountered as a dormant DoD legacy ASN. WHOIS resolves to the U.S. DoD via DISA-Columbus; not currently routed. Clean, no abuse signal. Abuse contact: disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil, +1-844-347-2457.