AS291

AS291 is a legacy autonomous system number registered under ARIN to ESnet, the Energy Sciences Network, the high-performance science network operated by Lawrence Berkeley National Laboratory on behalf of the U.S. Department of Energy's Office of Science. The ARIN handle is ESNET-EAST, the registration carried over from ESnet's historical eastern segment. The key triage point for AS291 is that it is an active but minimally-routed stub: every routing source consulted (RIPEstat, CAIDA AS Rank) agrees it currently originates exactly one IPv4 prefix — 198.124.0.0/14, totalling 262,144 addresses — and announces zero IPv6. RIPEstat sees the single prefix from 324 of 325 RIS peers (99.7% v4 visibility), and CAIDA records an AS degree of total 1 (customer 0, peer 0, provider 1), i.e. a stub AS sitting behind a single upstream provider with no downstream customers or visible peers. Despite that small footprint, CAIDA marks AS291 as a clique member, consistent with ESnet's role as a federally-funded research backbone that takes full transit. ESnet's operationally dominant, PeeringDB-listed ASN for production BGP routing is AS293; AS291 (ESNET-EAST) is the legacy ARIN-registered handle. The ARIN RDAP autnum top-level events record a registration (allocation) date of 1997-06-17 and a last-changed date of 2012-04-02. No notable public abuse signal was found as of June 2026 — not in Spamhaus DROP/ASN-DROP, NANOG archives, or threat feeds — consistent with a clean ASN held by a respected U.S. government R&E operator.

Operator

Energy Sciences Network (ESnet), operated by Lawrence Berkeley National Laboratory; ARIN handle ESNET-EAST; registrant org ENSN-Z, Berkeley, CA [Confirmed] — ARIN RDAP autnum/291, es.net/about

Country / RIR

US, ARIN [Confirmed] — RIPEstat abuse-contact-finder (authoritative_rir: arin), ARIN RDAP

Allocated

1997-06-17 (ARIN registry date from autnum top-level registration event); last changed 2012-04-02 [Confirmed] — ARIN RDAP autnum/291 top-level events

Org status

U.S. federal government-funded research network operated as part of a DOE national laboratory (Lawrence Berkeley National Laboratory); ESnet formed 1986 from HEPnet and MFEnet [Confirmed] — es.net/about, en.wikipedia.org/wiki/Energy_Sciences_Network

Contacts

hostmaster@es.net; HQ Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 59R3103, Berkeley, CA 94720, US [Confirmed] — ARIN RDAP autnum/291, RIPEstat abuse-contact-finder

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-25 — not on Spamhaus DROP/ASN-DROP, no NANOG incident discussions, no threat-feed flags; ESnet maintains a dedicated cybersecurity team [Likely; negative findings from web-indexed evidence, no live API queries] — spamhaus.org/blocklists/do-not-route-or-peer, es.net/about/esnet-staff/cybersecurity

Network & routing

Network type

U.S. federal research-and-education / government backbone; funded by the DOE Office of Science, stewarded by Lawrence Berkeley National Laboratory [Confirmed] — es.net/about

Size

active stub — 1 IPv4 prefix (198.124.0.0/14 = 262,144 addresses), 0 IPv6 prefixes; customer cone = 1 ASN (itself), 1 prefix, 262,144 addresses [Confirmed] — RIPEstat routing-status / announced-prefixes, CAIDA AS Rank

Routing/peering

announced — 324/325 v4 RIS peers see AS291; 0/323 v6 (no IPv6 originations); CAIDA degree total 1 (customer 0, peer 0, provider 1) — single upstream, no customers/peers; first seen routing 2000-08-18, last seen 2026-06-25 [Confirmed] — RIPEstat routing-status, CAIDA AS Rank. ESnet's production peering (Selective policy, peering@es.net) runs under AS293

[Confirmed for AS293 policy] — es.net peering-connections

RPKI

not assessed in this pass — RIPEstat rpki-validation requires a prefix argument and was skipped [Unknown] — RIPEstat rpki-validation (skipped, no prefix supplied)

Notable usage

ESnet is the backbone for DOE's national laboratories and user facilities, carrying large-scale scientific data transfer (high-energy physics, genomics, fusion, climate). AS291 (ESNET-EAST) is the legacy ARIN handle for the eastern segment; production routing now runs under AS293 [Confirmed for ESnet mission/AS293; Likely for legacy-eastern-segment framing] — es.net/about, en.wikipedia.org/wiki/Energy_Sciences_Network, peeringdb.com/asn/293

Related ASNs

AS293 (ESnet's active, PeeringDB-listed production network) [Confirmed] — peeringdb.com/asn/293, es.net peering-connections

Analyst note

Encountered as a legacy ARIN handle (ESNET-EAST) registered to ESnet that is active but routes a single /14 from one upstream; ESnet's production routing runs under AS293. Clean, low-footprint ASN under a respected U.S. government R&E operator.