AS231

AS231 is an autonomous system registered under ARIN to Michigan State University (MSU), the public land-grant research university founded in 1855 in East Lansing, Michigan. The ASN (ARIN handle MISU-231) carries the MSUnet campus backbone, serving roughly 50,000 students, faculty, and staff plus outlying MSU research centers. Four routing sources (bgp.tools, bgp.he.net, ipinfo.io, ipapi.is) agree it originates 7 IPv4 prefixes and 2 IPv6 prefixes — the IPv4 footprint anchored by the large legacy blocks 35.8.0.0/13 and 35.20.0.0/14, totaling roughly 787K addresses, plus four /24s in the 192.108.x/192.231.x range; IPv6 is 2605:dd00::/32 and 2605:dd00:8000::/48. MSU connects upstream exclusively through education/research networks: Merit Network, Inc. (AS237) and Internet2 I2PX (AS11164), with additional peering toward AS229 (Merit) and AS11537 (Internet2). This is a classic education-sector stub network — CAIDA reports an AS rank of 7,711, a customer cone of 2 ASNs / 9 prefixes, and a small degree (3 providers, 1 customer). Historically notable: MSU was a co-founder of Merit Network in 1966, the operator of the NSFNET backbone. The ARIN RDAP autnum top-level registration event is dated 2021-06-28 (a migration/re-registration; MSU's ARIN contact handles date to 2004, and the MISU org record to 1991). RPKI posture is partial — the three large IPv4 blocks carry valid ROAs while the four /24s and both IPv6 prefixes are unauthenticated; no RPKI-invalid routes were observed, though bgp.he.net flags AS231 as announcing bogons (likely the legacy 35.x space tripping older filters). No notable public abuse signal was found as of 2026-06-19: AS231 is absent from the Spamhaus DROP list, no ThreatFox/AbuseIPDB listing surfaced, and no NANOG abuse threads were specific to it. The documented MSU security incidents (2016 data breach, 2020 Netwalker ransomware, 2023 MOVEit supply-chain) were all inbound attacks on MSU systems or third-party vendors, not outbound abuse sourced from AS231. Abuse contact: abuse@msu.edu.

Operator

Michigan State University (public land-grant research university; ARIN handle MISU-231, East Lansing, MI) [Confirmed] — ARIN RDAP autnum/231, msu.edu/about

Country / RIR

US, ARIN [Confirmed] — ARIN RDAP autnum/231

Allocated

2021-06-28 (ARIN RDAP autnum top-level registration event date, 2021-06-28T10:56:13-04:00 — a first-party RIR fact, NOT an IEEE date; IEEE publishes no ASN registration dates) [Confirmed] — ARIN RDAP autnum/231. Context: this is a migration/re-registration event; MSU's ARIN contact handles (ATS14-ARIN, DTS21-ARIN) register from 2004-01-14 and the MISU org record from 1991-07-24 (org-record dates are NOT the ASN allocation date)

Org status

public state institution — a constitutional body of the State of Michigan, governed by an elected Board of Trustees; Michigan's designated land-grant university; tax-exempt as a state instrumentality (not a private nonprofit) [Confirmed] — msu.edu/about, brand.msu.edu/storytelling/msu-history

Contacts

abuse@msu.edu; +1-517-432-6200; dnstech@msu.edu; IT Services, 450 Auditorium Rd., Suite 400, East Lansing, MI 48824 [Confirmed for abuse/RDAP; ipapi.is/asn/231, ARIN RDAP autnum/231, ipinfo.io/AS231]

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-19 — absent from Spamhaus DROP (list dated 2026-06-12), no ThreatFox/AbuseIPDB listing surfaced (bot-challenge walls blocked direct reads; index absence is consistent with no listing but Unknown), no AS231-specific NANOG abuse threads. Documented MSU incidents (2016 ~400K-record breach, 2020 Netwalker ransomware, 2023 MOVEit) were INBOUND attacks on MSU/third-party systems, not outbound abuse from AS231

Network & routing

Network type

education / R&E campus network (MSUnet); classified eyeball by BGP tools due to day/night academic traffic rhythm; weekday-heavier, peak ~13:00–14:00 local [Confirmed] — bgp.tools/as/231, ipinfo.io/AS231, ipapi.is/asn/231

Size

7 IPv4 prefixes (35.8.0.0/13, 35.12.240.0/21, 35.20.0.0/14, 192.108.188.0/24, 192.108.190.0/24, 192.108.191.0/24, 192.231.113.0/24), ~787K addresses; 2 IPv6 prefixes (2605:dd00::/32, 2605:dd00:8000::/48) [Confirmed] — ARIN RDAP autnum/231, bgp.he.net/AS231, bgp.tools/as/231. (A5's "14 originated / 1.58M addresses" is an outlier; the prefix-list math and three other sources support ~787K / 7 prefixes)

Routing/peering

upstreams AS237 (Merit Network) and AS11164 (Internet2 I2PX); peers AS237, AS229 (Merit), AS11164, AS11537 (Internet2); CAIDA AS rank 7,711, customer cone 2 ASNs / 9 prefixes / 788,480 addresses, degree total 4 (providers 3, customer 1, peers 0); 100% RIS visibility (327/327 v4, 324/324 v6) [Confirmed] — bgp.he.net/AS231, bgp.tools/as/231, CAIDA AS Rank. (Note: ipinfo/bgp.tools popularity rank ~#1,090 of 42,367 / #156 US is a separate traffic-popularity metric, distinct from the CAIDA topology rank)

Peering policy

no published policy on msu.edu or PeeringDB (PeeringDB /asn/231 returns 404 — no listing); effective posture is selective, peering only with Merit and Internet2 R&E networks, consistent with a campus stub [Likely] — bgp.tools/as/231, tech.msu.edu/network/services

RPKI

partial — 35.8.0.0/13, 35.12.240.0/21, 35.20.0.0/14 carry valid ROAs; the four /24s and both IPv6 prefixes are unauthenticated; no RPKI-invalid routes observed; bgp.he.net flags bogon announcements (likely legacy 35.x space) [Likely] — bgp.he.net/AS231, bgp.tools/as/231

Notable usage

MSUnet campus backbone for 50,000+ users; participates in MiNet (high-speed MI research network via Merit, jointly with U-Michigan and Wayne State) and BTAA OmniPoP (Big Ten Academic Alliance 10–100 Gbps fiber); MSU co-founded Merit Network in 1966

[Confirmed] — tech.msu.edu/network/services, en.wikipedia.org/wiki/Merit_Network

Related ASNs

AS237 (Merit, MSU's primary upstream and co-founded network), AS229 (Merit), AS11164/AS11537 (Internet2) [Confirmed] — bgp.tools/as/231

Analyst note

Active education-sector campus network for a major US land-grant university; clean abuse posture; the only nuance is the 2021-06-28 RDAP date reflecting a registry migration rather than original allocation — recorded as the autnum top-level registration fact per the registry.