AS597

AS597 (CENTURYLINK-LEGACY-LVLT-597) is a legacy autonomous system number registered under ARIN to Level 3 Parent, LLC, a subsidiary of Lumen Technologies (formerly CenturyLink, and before that Level 3 Communications). ARIN's RDAP record places the ASN's original registration on 2002-06-05, with the top-level autnum record last changed 2019-12-04. AS597 sits within the AS594-AS598 legacy Level 3 numbering block and today functions purely as an inactive registry holding: every routing source consulted — RIPEstat, bgp.he.net, bgp.tools, and CAIDA AS Rank — agrees it has announced zero IPv4 and zero IPv6 prefixes since roughly August 2014, when its last IPv4 prefixes dropped out of the global routing table. CAIDA ranks it near the bottom of its global list (rank 79459) with a customer cone limited to the ASN itself and zero measured AS-degree links in any direction. Despite the routing dormancy, the underlying ARIN registration remains active rather than revoked, and Lumen has kept a dedicated RPKI/ROA-creation contact (RPKIR-ARIN, registered 2024) attached to the object, suggesting the number is retained for potential future route-origin authorization use rather than abandoned outright. Historical peer and upstream context ties AS597 to sibling Level 3/Lumen ASNs AS3356 and AS3549, both of which remain live on the Lumen backbone today. No public abuse or security signal was found for AS597 in Spamhaus's ASN-DROP feed or in a targeted NANOG mailing-list search conducted July 2026.

Operator

Level 3 Parent, LLC (Lumen Technologies subsidiary; formerly CenturyLink / Level 3 Communications; ARIN org handle LPL-141, 100 CenturyLink Drive, Monroe, LA) [Confirmed] — https://rdap.arin.net/registry/autnum/597, https://www.lumen.com/en-us/home.html

Country / RIR

US, ARIN [Confirmed] — https://rdap.arin.net/registry/autnum/597

Allocated

2002-06-05 (ARIN RDAP autnum TOP-LEVEL registration event, read from the untruncated autnum object's events[]; corroborated independently by three research angles, not an entity-level decoy date); last changed 2019-12-04 [Confirmed] — https://rdap.arin.net/registry/autnum/597

Org status

active ARIN registration, not de-registered or revoked; retained by Level 3 Parent, LLC / Lumen Technologies as a legacy holding within the AS594–AS598 Level 3 block [Likely] — https://rdap.arin.net/registry/autnum/597, https://bgp.he.net/AS597

Security/abuse context (NEUTRAL, DATED)

no notable public abuse signal found as of 2026-07-16 — not in Spamhaus ASN-DROP; no AS597-specific NANOG mailing-list threads located in a targeted search

Abuse contact

abuse@aup.lumen.com (per RDAP registrant remarks on org LPL-141); RIPEstat's abuse-contact-finder also surfaces abuse@level3.com (entity LAC56-ARIN)

Network & routing

Network type

legacy Level 3 Communications ASN within the AS594–AS598 legacy block; dormant — not seen in the global routing table since roughly August 2014 [Confirmed] — https://bgp.he.net/AS597, https://bgp.tools/as/597

Size

0 IPv4 prefixes / 0 IPv4 addresses / 0 IPv6 prefixes currently announced; historically 5 IPv4 prefixes originated; customer cone = 1 ASN (itself), 0 prefixes, 0 addresses; CAIDA AS rank 79459 [Confirmed] — https://stat.ripe.net/AS597, https://asrank.caida.org/asns/597, https://bgp.he.net/AS597

Routing/peering

not currently announced — CAIDA AS-degree total 0 (customer 0, peer 0, provider 0); no live upstream or peer sessions [Confirmed]. Historical (pre-2014) peer/upstream context ties AS597 to sibling Level 3/Lumen ASNs AS3356 and AS3549

[Likely] — https://bgp.he.net/AS597, https://asrank.caida.org/asns/597

RPKI

not directly assessable — AS597 announces no prefixes, so no ROA-vs-route validation is possible; RDAP lists a dedicated RPKI/ROA-creation contact entity (RPKIR-ARIN, "For creating ROKI ROA's", registered 2024-06-17) attached to the object, indicating Lumen retains RPKI tooling for the number

[Confirmed] — https://rdap.arin.net/registry/entity/RPKIR-ARIN

Peering policy

no AS597-specific policy found; Lumen's company-wide settlement-free peering policy (last revised 2021-09-09) governs its live ASN AS3356, not the dormant AS597 [Confirmed] — https://www.lumen.com/en-us/about/legal/peering-policy.html

Notable usage

legacy Level 3 Communications numbering; historically originated 5 IPv4 prefixes, last visible in the DFZ around 2014-08 [Confirmed] — https://bgp.he.net/AS597, https://stat.ripe.net/AS597

Related ASNs

AS3356, AS3549 (both current Lumen/Level 3-numbered ASNs; historical peer/upstream context only) [Likely] — https://bgp.he.net/AS597

Analyst note

registry-active but routing-dormant since ~2014; RPKI contact entity present but unused given zero current announcements. allocated_date is a first-party ARIN RDAP fact (autnum top-level registration event) and is recorded per pipeline policy, not nulled as a "non-IEEE"/database-artifact case — that caveat applies only to third-party MAC/OUI date scrapes.