asn.dev

Autonomous system

AS51572 CERULEAN

Unclassified RIPE

IPv4 addresses 2.05K 1 prefixes
IPv6 prefixes 0 counted as prefixes, not addresses
Countries 1 mostly GB
Exchanges 0 recorded by PCH
Upstreams 1 0 downstream
Flagged prefixes 0 none

Summary

Cerulean Solutions Limited

United Kingdom · AI-generated

business it-services london

The AS handle CERULEAN is held by Cerulean Solutions Limited.

What it's used for

  • The address space carries a single IPv4 block, 46.16.80.0/21, with the netname UK-CERULEAN-20100930 and registrant Cerulean Solutions Limited.
  • The network announces 2048 IPv4 addresses across 1 prefix and maintains 1 observed neighbour, a ratio consistent with a small, self-contained corporate estate rather than a transit or large access network.
  • As an IT support and managed services provider operating in London and South East England, the traffic from this AS consists of office workers, web/API endpoints, and internal business applications.

Notable

  • The RDAP registrant Cerulean Solutions Limited matches the AS holder, confirming direct ownership of the announced space.
  • The inventory consists of a single contiguous /21 block, indicating a straightforward internal corporate allocation without complex subdivision or multi-site segmentation.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy. Source, and how to suggest an edit.

Interconnection

Peering at a glance

Full topology · Graph

Internet exchanges

No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.

Transit providers

1 upstream, 0 downstream and 1 adjacent networks observed; most-used upstreams first.

ASNetworkPaths seen
AS25577MAINFRAME & CYBERNETIC SYSTEMS LIMITED58

Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-18, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.

Address space

Summary

Shape and geography

IPv4 1 prefixes · 2.05K addresses IPv6 0 prefixes

CountryNamePrefixes
GBUnited Kingdom1

Registry

Allocation record

RIPE · via Atlas (registry + RDAP)
Registry
RIPE
Handle
AS51572
Registry name
CERULEAN
Registrant
CERULEAN-MNTR
Abuse contact
abuse@cerulean.co.uk
Registered
2010-09-30
Last changed
2025-10-24
Allocation
allocated

Routing security

RPKI and IRR

Full detail
RPKI
0% valid · 0 valid, 1 with no ROA
ROAs
0 authorising AS51572
ASPA
no ASPA record
IRR
100% registered · 1 of 1 announcements
Route objects
1 naming AS51572

Reputation

Classification and threat

Unclassified Not in the curated lists. Most of the ~80,000 allocated ASNs are not.

Spamhaus DROP

Not on ASN-DROP The network as a whole is not listed.

No DROP prefixes None of its announced space is on the DROP prefix list.

Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 442 networks and 1,784 prefixes, as published 2026-10-19. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.

FBI IC3

No IC3 indicators Nothing from the FBI IC3 feed.

IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.

Elsewhere

Cross-check