AS31

AS31 is a legacy single-digit-era allocation registered under ARIN to the California Institute of Technology, and it remains a live campus/research network. It originates its flagship legacy class-B block 134.4.0.0/16 (registered 1989) plus 131.215.x and 192.12.19.0/24 ranges — about twelve IPv4 prefixes and one IPv6 prefix (~515 /24s of IPv4 and 65,536 /48s of IPv6) — taking transit from CENIC/CalREN (AS2152) and Cloudflare (AS13335), with roughly three peers. (Some snapshots also observe Los Nettos/AS226 as a transit path, so the exact transit set is snapshot-dependent.) The ARIN ASN RegDate of 1984-09-21 is the registry date (updated 2003-08-07). For triage this is a standard low-risk university allocation, actively routed via California research networks. No notable public abuse signal was found as of June 2026.

Operator

California Institute of Technology (ARIN OrgId CIT-4, Pasadena, CA) [Confirmed] — ARIN RDAP

Country / RIR

US, ARIN [Confirmed]

Allocated

ARIN ASN RegDate 1984-09-21 (registry date; updated 2003-08-07) [Confirmed]

Org status

active — caltech.edu

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-08; clean academic network — bgp.tools

Network & routing

Network type

research / education (university) [Confirmed]

Size

12 IPv4 prefixes, 1 IPv6 (~515 /24s); incl. 134.4.0.0/16, 131.215.x, 192.12.19.0/24 — bgp.tools (2026-06)

Routing/peering

actively announcing; 2 upstreams (CENIC/CalREN AS2152, Cloudflare AS13335), ~3 peers (AS226/Los Nettos observed as transit in some snapshots); RPKI unknown — bgp.tools

Notable usage

Caltech campus/research routing; originates legacy 134.4.0.0/16 (registered 1989) — caltech.edu

Related ASNs

none specifically confirmed for this profile

Analyst note

Standard low-risk university allocation; actively routed via California research networks.