AS43

AS43 is a legacy allocation registered under ARIN to Brookhaven National Laboratory, a U.S. Department of Energy Office of Science national lab (operated by Brookhaven Science Associates) hosting facilities such as RHIC and NSLS-II. RFC 1020 (1987) labeled it "BNL-AS," and the current holder matches that historical label. It is actively announcing: about five IPv4 prefixes and three IPv6 prefixes, with a single upstream — AS293 (ESnet, the DOE Energy Sciences Network) — and one peer, status Active/Allocated under ARIN. The ARIN ASN RegDate is 1985-04-11. For triage this is an active DOE national-lab network reachable via ESnet, carrying benign research traffic. No notable public abuse signal was found as of June 2026.

Operator

Brookhaven National Laboratory (ARIN; operated by Brookhaven Science Associates) [Confirmed] — ARIN RDAP

Country / RIR

US, ARIN [Confirmed]

Allocated

ARIN ASN RegDate 1985-04-11 [Confirmed] — bgp.tools (ARIN echo)

Org status

active — bnl.gov

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-06-09; benign national-lab traffic — bgp.tools

Network & routing

Network type

government / research (US DOE Office of Science national laboratory) [Confirmed]

Size

5 IPv4 prefixes, 3 IPv6 — bgp.tools (2026-06)

Routing/peering

actively announcing; single upstream AS293 (ESnet), 1 peer; RPKI unknown — bgp.tools

Notable usage

[historical, RFC 1020 + ARIN] AS43 "BNL-AS" = Brookhaven National Laboratory, a multidisciplinary DOE lab (RHIC, NSLS-II) — bnl.gov

Related ASNs

AS293 (ESnet — upstream) [Confirmed]

Analyst note

An active DOE national-lab network reachable via ESnet; benign research traffic.