asn.dev

Autonomous system

AS21301 RBS-FM-AS

Unclassified APNIC

IPv4 addresses 2.30K 5 prefixes
IPv6 prefixes 0 counted as prefixes, not addresses
Countries 1 mostly GB
Exchanges 0 recorded by PCH
Upstreams 3 0 downstream
Flagged prefixes 0 none

Summary

Natwest Markets PLC

United Kingdom · AI-generated

business financial uk

RBS-FM-AS is operated by Natwest Markets PLC.

What it's used for

  • The address space carries internal corporate infrastructure, evidenced by netnames such as UK-NATWEST-155-136-0-0-16 and the registrant Technical Role.
  • The AS announces 1792 IPv4 addresses across 3 prefixes and maintains 3 observed neighbours, a ratio consistent with a small, self-contained business network rather than a transit or access provider.

Notable

  • All three announced prefixes share the same netname UK-NATWEST-155-136-0-0-16 and registrant Technical Role, indicating a unified internal estate.
  • The address inventory consists of three blocks within the 155.136.0.0/16 range, specifically 155.136.56.0/22, 155.136.200.0/23, and 155.136.151.0/24.

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

3 upstream, 0 downstream and 3 adjacent networks observed; most-used upstreams first.

ASNetworkPaths seen
AS32787Akamai Technologies, Inc.551
AS1273IDDQD-AS117
AS2856British Telecommunications Limited61

Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-28, 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 5 prefixes · 2.30K addresses IPv6 0 prefixes

CountryNamePrefixes
GBUnited Kingdom5

Registry

Allocation record

APNIC · via Atlas (registry + RDAP)
Registry
APNIC
Handle
AS21301
Registry name
UK-NATWEST-AS21301
Registrant
Natwest Markets PLC
Abuse contact
abuse.cz@o2.com
Registered
2001-10-24
Last changed
2026-04-10
Allocation
allocated

Routing security

RPKI and IRR

Full detail
RPKI
0% valid · 0 valid, 15 with no ROA
ROAs
0 authorising AS21301
ASPA
no ASPA record
IRR
100% registered · 15 of 15 announcements
Route objects
32 naming AS21301

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: 448 networks and 1,851 prefixes, as published 2026-10-29. 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