AS233

AS233 is a legacy autonomous system number registered under ARIN to Merit Network, Inc., a nonprofit research-and-education (R&E) network founded in 1966 and governed by Michigan's public universities. Like its sibling AS181, AS233 carries early-Internet provenance: Merit operated the NSFNET backbone — the direct predecessor of the modern commercial Internet — from 1987 to 1995 under a National Science Foundation award, founded and administered NANOG (the North American Network Operators' Group) from 1994 until roughly 2010–2011, and founded and still operates RADb, one of the largest public Internet Routing Registries. The ARIN RDAP record dates the AS233 allocation to 1988-09-12 (autnum top-level registration event), placing it among the earliest ASNs ever assigned, with the registry last changed 2012-04-02. The key triage point for AS233 is that it is effectively dormant today: both routing sources consulted (bgp.he.net and bgp.tools) agree it announces zero IPv4 and zero IPv6 prefixes, has zero visible BGP peers, zero upstreams, and zero customers, and ipinfo.io confirms no current AS rank. Merit's active operational routing runs under AS237 (MERIT-AS-14); AS233 reads as a legacy or administrative allocation predating that model. RPKI posture cannot be assessed for AS233 because there are no active originations and therefore no ROAs. No notable public abuse signal was found as of June 2026 — not in Spamhaus ASN-DROP, the ipapi.is top-1000 abusive-ASN list, CleanTalk, or NANOG archives — consistent with a clean, dormant ASN held by a respected R&E operator. Merit itself is a defensive-security research organization, operating the ORION Network Telescope and leading the National Distributed Network Telescope (NDNT), so it is a network defender rather than a threat source.

Operator

Merit Network, Inc. (independent nonprofit R&E network governed by Michigan's public universities; ARIN registrant handle MICH-Z, Ann Arbor, MI) [Confirmed] — ARIN RDAP autnum/233, merit.edu/about

Country / RIR

US, ARIN [Confirmed] — ARIN RDAP autnum/233

Allocated

1988-09-12 (ARIN RDAP autnum top-level registration event — a first-party RIR fact, NOT an IEEE date and NOT a database artifact; IEEE publishes no ASN registration dates); last changed 2012-04-02 [Confirmed] — ARIN RDAP autnum top-level events[]

Org status

active independent nonprofit corporation (Merit Network), founded 1966 as the Michigan Educational Research Information Triad by the University of Michigan, Michigan State University, and Wayne State University; member-governed by Michigan's public universities; operated NSFNET under an NSF award

[Confirmed] — merit.edu/about, merit.edu/about/history, en.wikipedia.org/wiki/Merit_Network

Contacts

abuse@merit.edu / +1-734-527-5740; operations@merit.edu (tech) / +1-734-527-5717; ipreg@merit.edu (admin) / +1-734-763-3448; HQ 880 Technology Drive, Suite B, Ann Arbor, MI 48108-8963 [Confirmed] — ARIN RDAP autnum/233

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-20 — not in Spamhaus ASN-DROP, not in the ipapi.is top-1000 abusive-ASN list (updated 2026-06-19), not in CleanTalk, and no AS233-specific NANOG abuse threads; the ASN holds no active IP space, which structurally removes most abuse vectors. Merit operates the ORION Network Telescope and leads the National Distributed Network Telescope — a defender/researcher, not a threat source [Confirmed] — spamhaus.org/drop/asndrop.json, ipapi.is/most-abusive-asn.html, cleantalk.org/blacklists/as233, merit.edu/research/national-distributed-network-telescope

Network & routing

Network type

regional research-and-education (R&E) backbone; AS233 is legacy/inactive (Merit's active network runs under AS237) [Confirmed] — merit.edu/about, ipinfo.io/AS233, bgp.he.net/AS233

Size

dormant — 0 IPv4 prefixes / 0 IPv4 addresses and 0 IPv6 prefixes; ipinfo.io reports 0 peers, 0 upstreams, 0 downstreams, no current ranking [Confirmed] — bgp.he.net/AS233, bgp.tools/as/233, ipinfo.io/AS233

Routing/peering

NOT announced — AS233 is absent from the global BGP table per both bgp.he.net and bgp.tools (0 prefixes v4/v6, 0 peers, 0 upstreams) [Confirmed]. Merit's active AS237 carries production traffic; AS233's own peering classification (open/selective/closed) is not published

[Unknown for AS233 policy] — bgp.he.net/AS233, bgp.tools/as/233, merit.edu/solutions/networking-security/peering-caching

RPKI

not assessable — AS233 announces no prefixes, so there are no ROAs to validate; 0 RPKI-valid and 0 RPKI-invalid origins observed [Confirmed] — bgp.he.net/AS233

Notable usage

Merit operated the NSFNET backbone (1987–1995; the network grew from 217 connected networks in July 1988 to 50,000+ by April 1995), founded and administered NANOG (1994–~2011), and operates RADb (IRR). AS233 (MERIT-AS-10) is an early/legacy Merit ASN registered 1988-09-12; active infrastructure now runs under AS237 [Confirmed] — merit.edu/research/projects/the-nsfnet-backbone-service, merit.edu/about/history, en.wikipedia.org/wiki/National_Science_Foundation_Network

Related ASNs

AS237 (MERIT-AS-14, Merit's active operational network); Merit holds additional adjacent ASNs in the AS229–238 block; AS231 (MISU-231, Michigan State University — Merit co-founder); Internet2 (AS11164/AS11537) [Confirmed for AS237/AS231/Internet2; Likely for the broader adjacent block] — bgp.tools/as/233, merit.edu/about, en.wikipedia.org/wiki/Merit_Network

Analyst note

AS233 is Merit Network's legacy ARIN allocation (MERIT-AS-10), registered 1988-09-12 and effectively dormant today — WHOIS resolves to Merit Network, but live routing runs under AS237, not AS233. allocated_date is RECORDED as 1988-09-12 from the ARIN RDAP autnum top-level registration event (a first-party RIR fact); entity-level events (org handle MICH-Z registered 2009-12-08 and contact handles registered 1999/2002/2007) were correctly excluded as decoys. Clean, inactive ASN; no community corroboration of abuse, outages, or disputes found.