AS26

AS26 is Cornell University's campus network ASN, an original 1984 allocation registered under ARIN and managed by Cornell Information Technologies in Ithaca, NY. It originates roughly seven to nine IPv4 prefixes plus one IPv6 prefix (~197,000 IPv4 addresses), including the well-known 128.253.0.0/16 block, and takes transit from Arelion (AS1299) and FirstLight Fiber (AS13536), with IRR references also naming Cloudflare (AS13335). For triage this is a clean, long-established academic allocation: encountering it indicates Cornell campus space, with the NOC reachable at noc@cornell.edu. One routing-hygiene note: Hurricane Electric shows one valid and one invalid IPv4 origination, which is an RPKI item to track rather than evidence of abuse. No notable public abuse signal was found as of June 2026.

Operator

Cornell University (ARIN OrgId CORNEL; Cornell Information Technologies, Ithaca, NY) [Confirmed] — ARIN RDAP

Country / RIR

US, ARIN [Confirmed]

Allocated

ASN RegDate 1984-08-10; updated 2022-03-29 [Confirmed] — ARIN

Org status

active (Cornell University)

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-07; routine higher-ed network (noc@cornell.edu) — bigdatacloud.com

Network & routing

Network type

research / education [Confirmed]

Size

~7–9 IPv4 prefixes, 1 IPv6 (~197,376 IPv4 addrs); incl. 128.253.0.0/16 — bgp.he.net / bgp.tools (2026-06)

Routing/peering

upstreams AS1299 (Arelion), AS13536 (FirstLight Fiber); IRR also references AS3630, AS3754, AS13335 (Cloudflare); RPKI mixed — HE shows 1 valid + 1 invalid IPv4 origination (routing-hygiene note) — bgp.he.net

Notable usage

Cornell University campus network ASN; original 1984 allocation managed by Cornell Information Technologies — cornell.edu

Related ASNs

unknown

Analyst note

A clean, long-established academic allocation; encountering it indicates Cornell campus space. Routine higher-ed network.