Autonomous system detail

AS605

Not announced

Operated by VHS-CHIL - Vanguard Health Management, Inc..

Summary

// analyst note
Dormant enterprise ASN belonging to a since-acquired hospital operator (Vanguard Health Systems -> Tenet Healthcare, 2013). All routing sources (RIPEstat, CAIDA, bgp.he.net) agree on zero current announcements; last live routing ended 2021-05-05.
// security note
NEUTRAL/DATED: no notable public abuse or threat-intel signal found as of 2026-07-16; bgp.he.net flags the withdrawn prefix 204.126.150.0/24 as a 'bogon', most plausibly a routing-staleness artifact rather than a confirmed abuse event.
IPv4 prefixes
0
~0 addresses
IPv6 prefixes
0
—
Peer networks
0
0 up · 0 down
IANA block
1-1876
Assigned by ARIN
[ 01 ] — Context

About this ASN.

Updated  ·  Confidence: High

AS605 (VHS-CHIL) is a small, dormant ARIN-registered autonomous system originally allocated 2009-07-21 to Vanguard Health Management, Inc., the Nashville, Tennessee-based operator behind the Vanguard Health Systems hospital network. The registrant record — ARIN org handle VANGU-18 — lists the same Burton Hills Boulevard address used by the parent hospital operator, which was acquired by Tenet Healthcare Corporation in a roughly $4.3 billion deal effective 2013-10-01; nothing in the registry suggests AS605 was reassigned or renamed after that acquisition, and it remains listed under the original Vanguard entity in RDAP to this day. The ASN saw limited operational use: RIPEstat and bgp.he.net agree it originated exactly one IPv4 prefix, 204.126.150.0/24, via a single observed upstream, AS2828 (Verizon Business, formerly UUNET/MCI), from 2010-03-05 until 2021-05-05, and it has been completely absent from the global routing table since. CAIDA ranks it near the bottom of its AS Rank table (#79459) with a customer cone consisting of just itself and zero measured AS relationships. The sole listed ARIN point of contact, John Squeo, has been flagged as unvalidated by ARIN since 2010-07-05, and no dedicated operator website or PeeringDB record exists for this ASN — consistent with a single-site enterprise network rather than a public ISP or peering participant.

Operator
Vanguard Health Management, Inc. (ARIN org handle VANGU-18; parent Vanguard Health Systems, Inc., Nashville, TN — acquired by Tenet Healthcare Corporation effective 2013-10-01) [Confirmed] — https://rdap.arin.net/registry/autnum/605, https://www.sec.gov/Archives/edgar/data/0000070318/000110465913073474/a13-21190_1ex99d1.htm
Country / RIR
US, ARIN [Confirmed] — RIPEstat abuse-contact-finder (authoritative_rir: arin)
AS name / handle
VHS-CHIL [Confirmed] — https://rdap.arin.net/registry/autnum/605
Allocated
2009-07-21 (ARIN RDAP autnum TOP-LEVEL registration event, first-party RIR fact); last changed 2020-05-14 [Confirmed] — https://rdap.arin.net/registry/autnum/605
Org status
parent Vanguard Health Systems, Inc. acquired by Tenet Healthcare Corporation effective 2013-10-01 (~$4.3B deal); the ASN itself has been unannounced/dormant since 2021-05-05
[Confirmed] — https://www.sec.gov/Archives/edgar/data/0000070318/000110465913073474/a13-21190_1ex99d1.htm, https://bgp.he.net/AS605

Abuse contact

an individual mailbox on the vanguardhealth.com domain, listed to POC John Squeo (personal address not republished here); ARIN flags this POC as unvalidated since 2010-07-05

[Confirmed] — https://rdap.arin.net/registry/autnum/605, https://stat.ripe.net/data/whois/data.json?resource=AS605

Security/abuse context (NEUTRAL, DATED)

no notable public abuse or threat-intelligence signal found as of 2026-07-16; bgp.he.net's "bogon" flag on the withdrawn prefix 204.126.150.0/24 is most plausibly a routing-staleness artifact rather than a confirmed abuse/hijack event

[Likely] — https://bgp.he.net/AS605, https://stat.ripe.net/data/whois/data.json?resource=AS605

Network & routing

Network type
enterprise/end-user ASN (healthcare system's internal multi-hospital network), not a transit or public peering network; no PeeringDB record exists (peeringdb.com/asn/605 returns 404) [Likely] — https://bgp.he.net/AS605, https://www.peeringdb.com/asn/605
Size / routing status
currently 0 IPv4 and 0 IPv6 prefixes announced; historically originated exactly one /24 (204.126.150.0/24) from 2010-03-05 to 2021-05-05 [Confirmed] — https://stat.ripe.net/AS605, https://bgp.he.net/AS605
Upstream/peers
no current peers or upstreams (0 RIS peers seeing it, 0 CAIDA AS degree); historical sole observed upstream was AS2828 (Verizon Business) [Confirmed] — https://stat.ripe.net/AS605, https://bgp.he.net/AS605
CAIDA AS Rank
#79459; customer cone = singleton (1 ASN, 0 prefixes, 0 addresses) [Confirmed] — https://asrank.caida.org/asns/605
RPKI
Unknown — RIPEstat's rpki-validation endpoint was skipped in the canonical payload (no prefix supplied) and no ROA data was corroborated [Unknown]
Registrant address
20 Burton Hills Blvd., Suite 100, Nashville, TN 37215, United States [Confirmed] — https://rdap.arin.net/registry/autnum/605
Community signal
no NANOG mailing-list or Reddit mentions found; no reported outages [Confirmed] — https://archive.nanog.org/list/archives/, https://seclists.org/nanog/
[ 02 ] — Announced prefixes

What this network routes.

0 prefixes total · RIPEstat data · cached, not real-time
// IPv4 prefixes0
No IPv4 prefixes announced.
// IPv6 prefixes0
No IPv6 prefixes announced.
[ 03 ] — Notable peers & upstreams

Who it talks to.

0 observed neighbours
Neighbour data unavailable from public BGP collectors.