AS511

AS511 is an ARIN-registered autonomous system number held by Prisma Health, a not-for-profit healthcare system headquartered in Greenville, South Carolina. Prisma Health was formed in November 2017 by the merger of Palmetto Health and the Greenville Health System, and it is now South Carolina's largest private nonprofit health system, with hospitals and outpatient sites across South Carolina and, following a 2024 acquisition, Tennessee. The ARIN RDAP autnum record's own top-level registration event dates AS511 to 2017-08-01, with a last-changed event of 2023-06-15 — this predates the merger's public announcement by a few months but falls within the run-up period, consistent with the ASN being provisioned ahead of the combined network's build-out. AS511 is a small enterprise/end-user ASN rather than a transit network: it announces a single IPv4 prefix, 199.15.151.0/24 (256 addresses), no IPv6, and shows only two BGP relationships in CAIDA's graph (both classified as providers, zero customers, zero peers), consistent with a single-site hospital-system network reached via two upstream transit providers rather than a network that peers publicly. No PeeringDB record exists for the ASN, and no public peering policy was found. No notable network-abuse signal (spam, botnet, DDoS-source, or BGP hijack) was found tied to AS511 or its announced prefix; Prisma Health (and its Palmetto Health predecessor) has disclosed HIPAA-reportable incidents as a breach *victim* — a 2019 employee-email phishing compromise and a separate website breach — but these are application/corporate-layer events unrelated to AS511's routed IP space.

Operator

Prisma Health (registrant org handle PH-713), 300 E. McBee Ave., Ste 302, Greenville, SC 29601 [Confirmed] — https://rdap.arin.net/registry/autnum/511 , https://whois.arin.net/rest/org/PH-713.html

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/511

Allocated

2017-08-01 (ARIN RDAP autnum TOP-LEVEL "registration" event, 2017-08-01T15:36:54-04:00 — a first-party RIR fact, distinct from the decoy entity-level dates on the PRISM3-ARIN/PH-713 contact and org records); last changed 2023-06-15 [Confirmed] — https://rdap.arin.net/registry/autnum/511

Org status

not-for-profit nonprofit health system, formed November 2017 by the merger of Palmetto Health and Greenville Health System; South Carolina's largest private nonprofit health system, with SC and (since 2024) Tennessee operations [Likely, secondary source] — https://en.wikipedia.org/wiki/Prisma_Health

Website / abuse contact

https://prismahealth.org/ ; prismanetwork-arin@prismahealth.org [Confirmed] — https://stat.ripe.net/data/abuse-contact-finder/data.json?resource=511

Security/abuse context (NEUTRAL, DATED)

no notable public network-abuse signal (spam, botnet C2, DDoS-source, or BGP hijack/route-leak) found for AS511 or 199.15.151.0/24 as of 2026-07-10 in Spamhaus DROP/ASN-DROP context pages, bgp.tools, or general search

Network & routing

Network type

enterprise/end-user network for a healthcare system, not a transit ISP or content network [Confirmed] — https://rdap.arin.net/registry/autnum/511; two BGP relationships classified as providers (Spirit Communications AS2711, Charter Communications AS20115) [Likely, third-party BGP-collector attribution] — https://bgp.he.net/AS511 , https://bgp.tools/as/511

Size

1 IPv4 prefix (199.15.151.0/24, 256 addresses); 0 IPv6 prefixes; customer cone = singleton (1 ASN, 1 prefix, 256 addresses) [Confirmed] — https://stat.ripe.net/data/announced-prefixes/data.json?resource=511 , https://asrank.caida.org/asns/511

Routing/peering

RIS visibility 327/327 v4 peers seeing the announced prefix, 0/321 v6; CAIDA degree total 2 (customer 0, peer 0, provider 2); no PeeringDB network record (404 at peeringdb.com/asn/511); no public peering policy found [Confirmed for routing metrics; Likely/Unknown for peering policy] — https://stat.ripe.net/data/routing-status/data.json?resource=511 , https://asrank.caida.org/asns/511 , https://www.peeringdb.com/asn/511

RPKI

Unknown — RIPEstat rpki-validation requires a prefix and was not queried; bgp.he.net independently shows no ROA/RPKI-valid or -invalid data recorded for AS511 [Unknown, sourced] — https://bgp.he.net/AS511

Notable usage

small single-site IPv4 footprint (~256 addresses) supporting Prisma Health's own hospital/clinical network infrastructure in the Greenville, SC area; no customer-facing internet-service usage [Likely] — https://ipinfo.io/AS511

ASN / AS name

AS511 / PRISMA HEALTH [Confirmed] — https://rdap.arin.net/registry/autnum/511

Registry hygiene note

bgp.he.net flags the announced prefix "IRR Invalid - Origin Mismatch" and a general bogon-announcement condition (third-party scrape, dated to fetch time, not a confirmed abuse signal) [Likely] — https://bgp.he.net/AS511

Related organizational incidents (NOT network abuse)

Prisma Health / predecessor Palmetto Health disclosed a 2019 employee-email phishing breach affecting 23,811 patients, and a separate website breach potentially affecting ~22,000 individuals — corporate/application-layer HIPAA incidents, not AS511 network-abuse [Likely] — https://www.hipaajournal.com/phi-of-23811-palmetto-health-patients-exposed-in-phishing-attack/ , https://www.hipaajournal.com/prisma-health-website-breach-potentially-impacts-22000-individuals/

Analyst note

Registrant is a healthcare system, not a traditional network operator, so several transit-operator-style fields (public peering policy, IX presence) are correctly Unknown rather than a research gap. No NANOG or Reddit community discussion of AS511 was found, consistent with a low-visibility single-site enterprise ASN.