AS181

AS181 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. The ASN carries notable historical weight: Merit operated the NSFNET backbone — the direct predecessor of the modern commercial Internet — from 1987 to 1995 under a National Science Foundation award, and it founded and administered NANOG, the North American Network Operators' Group, from 1994 until roughly 2010–2011. Merit also founded and still operates RADb, one of the largest public Internet Routing Registries. The key triage point for AS181 is that it is effectively dormant today: every routing source consulted (RIPEstat, CAIDA AS Rank, bgp.he.net, bgp.tools) agrees it announces zero IPv4 and zero IPv6 prefixes, has zero visible BGP peers, zero upstreams, zero customers, and no IXP memberships. Its CAIDA AS rank of 79,459 sits near the bottom of the global ranking, reflecting complete routing inactivity, and its customer cone is a singleton (the ASN itself, 0 prefixes, 0 addresses). Merit's active operational routing runs under AS237, which carries roughly 300–500 Gbps of traffic over about 4,000 miles of owned fiber and runs a Selective peering policy. RPKI posture cannot be assessed for AS181 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, CleanTalk, NANOG archives, or CISA advisories — consistent with a clean, dormant ASN held by a respected R&E operator.

Operator

Merit Network, Inc. (nonprofit R&E network; ARIN handle MERIT-AS-1, Ann Arbor, MI) [Confirmed] — ARIN RDAP, merit.edu/about

Country / RIR

US, ARIN [Confirmed] — RIPEstat abuse-contact-finder (authoritative_rir: arin)

Allocated

1988-04-28 (ARIN registry date, NOT an IEEE date — 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), governed by Michigan's public universities; founded 1966; operated NSFNET under a ~$39M NSF award [Confirmed] — merit.edu/about/history

Contacts

abuse@merit.edu; noc@merit.edu; operations@merit.edu; HQ 880 Technology Drive, Suite B, Ann Arbor, MI 48108 [Confirmed for abuse/RIR via RIPEstat; Likely for NOC/HQ via RDAP mirrors]

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-18 — not in Spamhaus ASN-DROP, CleanTalk (empty metrics), NANOG archives, or CISA/CERT advisories; dormant ASN under a respected R&E operator — spamhaus.org/drop/asndrop, cleantalk.org/blacklists/as181

Network & routing

Network type

regional research and education (R&E) network; AS181 is legacy/inactive (Merit's active network runs under AS237) [Confirmed] — merit.edu/about, peeringdb.com/asn/237

Size

dormant — 0 IPv4 prefixes / 0 IPv4 addresses and 0 IPv6 prefixes; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses — RIPEstat routing-status / CAIDA AS Rank / bgp.he.net / bgp.tools (2026-06)

Routing/peering

NOT announced — 0 RIS peers seeing it (0/327 v4, 0/323 v6); CAIDA degree total 0 (customer 0, peer 0, provider 0); no upstreams or peers visible in any source [Confirmed]. Merit's active AS237 runs a Selective peering policy (peering@merit.edu) [Likely for AS237 policy]

RPKI

not assessable — AS181 announces no prefixes, so there are no ROAs to validate; bgp.he.net shows 0 RPKI-valid and 0 RPKI-invalid origins [Confirmed]

Notable usage

Merit operated the NSFNET backbone (1987–1995), founded and administered NANOG (1994–~2011), and operates RADb (IRR). AS181 (MERIT-AS-1) is an early/legacy Merit ASN; active infrastructure now runs under AS237 — merit.edu/about/history, peeringdb.com/asn/237

Related ASNs

AS237 (Merit's active operational network); Merit holds additional ASNs (e.g. AS182–185, AS229–230, AS232–233, AS235–238, AS689, AS750–759, others) [Confirmed for AS237; Likely for the broader block list per third-party DB]

Analyst note

Encountered as a dormant legacy ASN registered to a historically significant R&E operator; WHOIS resolves to Merit Network, but live routing is under AS237, not AS181. Clean, inactive ASN.