AS40

AS40 is a legacy allocation registered under ARIN to the Massachusetts Institute of Technology (org MIT-2, the Cambridge campus), carrying the historical handle "MIT-TEST" — an MIT test AS. A common assumption ties AS40 to MIT Lincoln Laboratory, but that is not what the registry or RFC 1020 show: the historical label is MIT-TEST, and Lincoln Lab's separate historical label "LL-MI" was AS63, a different number. The ASN appears dormant in 2026, showing no IPs, peers, or upstreams; MIT's live routing runs under AS3 (MIT-GATEWAYS) — which originates roughly 100+ IPv4 prefixes with many peers and upstreams — and AS396527. For triage this is a dormant legacy MIT number; current MIT traffic is on AS3, not AS40. The ARIN ASN RegDate of 1985-02-28 is the registry date (updated 2011-06-23). No notable public abuse signal was found as of June 2026.

Operator

Massachusetts Institute of Technology (ARIN OrgId MIT-2) [Confirmed] — ARIN RDAP

Country / RIR

US, ARIN [Confirmed]

Allocated

ARIN ASN RegDate 1985-02-28 (registry date; updated 2011-06-23) [Confirmed]

Org status

organization active, ASN dormant

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-08; dormant legacy number — IPinfo

Network & routing

Network type

research / education [Confirmed]

Size

appears dormant; no IPs/prefixes — IPinfo (2026-06)

Routing/peering

none currently from AS40; RPKI none — IPinfo

Notable usage

[historical, RFC 1020 + ARIN] AS40 "MIT-TEST" = an MIT test AS, registered to MIT proper (org MIT-2). NOT MIT Lincoln Laboratory (Lincoln Lab's historical "LL-MI" was AS63) — mit.edu

Related ASNs

AS3 (MIT-GATEWAYS — current live MIT routing), AS396527 [Confirmed]

Analyst note

A dormant legacy MIT number; MIT's live routing runs under AS3, not AS40. Not Lincoln Laboratory (that was AS63).