AS166

AS166 is registered under ARIN to the Institute for Defense Analyses (IDA), a private U.S. non-profit corporation headquartered at 730 E Glebe Rd, Alexandria, VA 22305. IDA administers three Federally Funded Research and Development Centers (FFRDCs) — the Systems and Analyses Center, the Science and Technology Policy Institute, and the Center for Communications and Computing — providing independent analysis to the U.S. Department of Defense and other federal agencies. AS166 is an enterprise/institutional network, not an ISP or transit provider: it is a dual-homed stub AS that originates IDA's own address space for internal research-campus routing. The ARIN RDAP record shows a registration event of 1988-03-29, making this one of the oldest ASNs in the ARIN registry (this is an ARIN registry/database artifact, not an IEEE-published date — IEEE publishes none). The AS record was last changed 2022-05-20, while the org/contacts records were refreshed 2025-11-17. AS166 announces roughly 18 IPv4 prefixes (~131,328 addresses, ~513 /24 equivalents) across blocks in 129.246.0.0/16 and 164.217.0.0/16, and originates no IPv6. It is dual-homed to exactly two upstream transit providers — Hurricane Electric (AS6939) and Lumen/Level 3 (AS3356) — with no downstream customers, so it is a pure stub/leaf AS. No RPKI ROAs are in place (effectively 0% coverage), and bgp.he.net flags at least one bogon announcement, though the specific prefix is not isolated in the fetched data. No notable public abuse signal was found as of June 2026; it presents as a clean, long-established government-research network with a small, stable footprint.

Operator

Institute for Defense Analyses (IDA); ARIN org handle IDA-2-Z, 730 E Glebe Rd, Alexandria, VA 22305, US [Confirmed] — ARIN RDAP (https://rdap.arin.net/registry/autnum/166)

Country / RIR

US, ARIN (ASN block 1–1876 assigned by ARIN) [Confirmed] — ARIN RDAP / RIPEstat as-overview

Allocated

ARIN RDAP registration event 1988-03-29 (registry/database artifact, NOT an IEEE date — IEEE publishes none); AS record last changed 2022-05-20; org/contacts last changed 2025-11-17 [Confirmed] — ARIN RDAP (https://rdap.arin.net/registry/autnum/166)

Org status

active private non-profit corporation (FFRDC administrator); primary sponsor U.S. Department of Defense; revenue ~$270M (2021); website https://www.ida.org [Confirmed] — Wikipedia (https://en.wikipedia.org/wiki/Institute_for_Defense_Analyses), ARIN RDAP

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-16; not on Spamhaus DROP/ASN-DROP or any indexed threat/blocklist feed; no NANOG discussion surfaced. CleanTalk (HTTP 403) and AbuseIPDB direct lookup (HTTP 403) could not be verified

Network & routing

Network type

enterprise/institutional research network (FFRDC administrator); not an ISP or transit provider; stub/leaf AS [Confirmed] — bgp.tools (https://bgp.tools/as/166), Wikipedia (https://en.wikipedia.org/wiki/Institute_for_Defense_Analyses)

Size

~18 IPv4 prefixes / ~131,328 addresses (~513 /24 equivalents); 0 IPv6; blocks in 129.246.0.0/16 and 164.217.0.0/16 [Confirmed] — bgp.he.net (https://bgp.he.net/AS166), bgp.tools (https://bgp.tools/as/166)

Routing/peering

dual-homed to exactly two upstreams — AS6939 (Hurricane Electric) and AS3356 (Lumen/Level 3); 0 downstream customers (pure stub); IPv4-only transit [Confirmed] — bgp.he.net (https://bgp.he.net/AS166), bgp.tools (https://bgp.tools/as/166)

Peering policy

no published public peering policy; no PeeringDB record found (peeringdb.com/asn/166 returned 404); effectively closed/transit-only [Likely] — peeringdb.com (https://www.peeringdb.com/asn/166), bgp.tools (https://bgp.tools/as/166)

RPKI posture

no ROAs detected — RPKI Originated Valid 0, Invalid 0; all announced prefixes RPKI state "Not Found"; ~0% coverage [Confirmed] — bgp.he.net (https://bgp.he.net/AS166)

Notable usage

internal IP infrastructure of the Institute for Defense Analyses (founded 1956), a national-security research organization serving DoD, NSA, DHS, DOE, NASA, and NSF; pronounced weekday day/night usage rhythm consistent with a research workforce

[Confirmed] — ipinfo.io (https://ipinfo.io/AS166), Wikipedia (https://en.wikipedia.org/wiki/Institute_for_Defense_Analyses)

AS rank / customer cone

AS rank Unknown (no CAIDA AS-rank data in inputs); customer cone is just the AS itself (0 customers, stub) [Confirmed for stub status; rank Unknown] — bgp.he.net (https://bgp.he.net/AS166)

Related ASNs

AS6939 (Hurricane Electric, upstream), AS3356 (Lumen/Level 3, upstream) [Confirmed] — bgp.he.net (https://bgp.he.net/AS166)

Bogon flag

bgp.he.net flags "AS166 announces bogons" — at least one announced prefix may overlap reserved/bogon space; specific prefix not isolated in fetched data [Likely] — bgp.he.net (https://bgp.he.net/AS166)

NOC / abuse contacts

Admin/Abuse/Technical — Chris Murphy (CMU49-ARIN); Routing/NOC/Technical — TPH61-IDA group (TPHID-ARIN); both on the ida.org domain, with individual mailboxes and direct lines in the ARIN RDAP record [Confirmed] — ARIN RDAP (https://rdap.arin.net/registry/autnum/166)

Analyst note

long-established (1988) U.S. defense-research stub network; WHOIS/RDAP resolves cleanly to IDA. Small, stable, US-only footprint. Notable gaps: no RPKI ROAs and a flagged bogon announcement.