AS27

AS27 is a legacy single-digit allocation registered under ARIN to the University of Maryland at College Park, and it is the genuine University of Maryland legacy ASN — not AS20, which is the University of Rochester. RFC 1020/1166 label it "UMDNET — University of Maryland at College Park," the same institution then and now. It actively announces about seven IPv4 prefixes and six IPv6 prefixes, roughly 139,745 IPv4 addresses (~546 /24s), receiving transit from AS10886 (also University of Maryland); bgp.tools classifies it Eyeball/Academic, ranking it around #1,460 of 76,394 by IPv4 space. The ARIN ASN RegDate of 1984-08-28 is the registry date (the org record's 2010 date is a refresh). For triage this is a major flagship-university network, actively routed, with a clean academic profile. No notable public abuse signal was found as of June 2026.

Operator

University of Maryland (College Park; ARIN OrgId UNIVER-262-Z) [Confirmed] — ARIN RDAP

Country / RIR

US, ARIN [Confirmed]

Allocated

ARIN ASN RegDate 1984-08-28 (registry date; org RegDate 2010-01-06 is a refresh) [Confirmed for shown date]

Org status

active — umd.edu

Security/abuse context (NEUTRAL, DATED)

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

Network & routing

Network type

research / education [Confirmed]

Size

7 IPv4 prefixes, 6 IPv6 (~139,745 IPv4 addrs, ~546 /24s) — bgp.tools / bigdatacloud.com (2026-06)

Routing/peering

actively announcing; receiving from / upstream AS10886 (University of Maryland); RPKI unknown — bgp.tools

Notable usage

University of Maryland College Park campus network; RFC 1020/1166 "UMDNET". NOT University of Rochester (that's AS20) — ipip.net

Related ASNs

AS10886 (University of Maryland), AS6059 (University System of Maryland), AS22877 (University of Maryland Global Campus) [Confirmed]

Analyst note

Major flagship-university network, actively routed; clean academic profile. This — not AS20 — is the University of Maryland legacy ASN.