Autonomous System
AS21054 Natwest Markets PLC
BankingActiveUnited KingdomRIPE
AS21054 (UK-NATWEST-AS21054) is a banking network operated by Natwest Markets PLC in United Kingdom, registered with RIPE. It has 11 IPv4 prefixes with 133,888 addresses, which makes it the 1,791st largest of 82,200 active autonomous systems by IPv4 space.
IPv4 addresses133,888in 11 prefixes
IPv6 prefixes0none
Size rank#1,791of 82,200 active ASNs
Details
OrganizationNatwest Markets PLC
AS nameUK-NATWEST-AS21054
Websitenatwestmarkets.com
Country United Kingdom (GB)
Network typeBanking
RegistryRIPE
Abuse contactripe-abuse@rbs.com
Registered2002-03-07
Last updated2026-04-10
IPv4 prefixes
11 prefixes · 133,888 addresses| Network | Addresses | First – last address |
|---|---|---|
| 155.136.0.0/16 | 65,536 | 155.136.0.0 – 155.136.255.255 |
| 155.136.0.0/17 | 32,768 | 155.136.0.0 – 155.136.127.255 |
| 155.136.128.0/17 | 32,768 | 155.136.128.0 – 155.136.255.255 |
| 155.136.60.0/22 | 1,024 | 155.136.60.0 – 155.136.63.255 |
| 155.136.60.0/24 | 256 | 155.136.60.0 – 155.136.60.255 |
| 155.136.61.0/24 | 256 | 155.136.61.0 – 155.136.61.255 |
| 155.136.62.0/24 | 256 | 155.136.62.0 – 155.136.62.255 |
| 155.136.63.0/24 | 256 | 155.136.63.0 – 155.136.63.255 |
| 155.136.197.0/24 | 256 | 155.136.197.0 – 155.136.197.255 |
| 155.136.202.0/24 | 256 | 155.136.202.0 – 155.136.202.255 |
| 155.136.203.0/24 | 256 | 155.136.203.0 – 155.136.203.255 |
155.136.0.0/16 155.136.0.0/17 155.136.128.0/17 155.136.60.0/22 155.136.60.0/24 155.136.61.0/24 155.136.62.0/24 155.136.63.0/24 155.136.197.0/24 155.136.202.0/24 155.136.203.0/24
IPv6 prefixes
No IPv6 prefixes.
Query AS21054 with the API
The ASN lookup returns everything on this page as JSON, including every prefix. ASN lookups need an API key: a free account comes with 1,000 requests a day.
curl "https://api.ipapi.is/?q=AS21054&key=YOUR_API_KEY"Any address in its prefixes resolves to AS21054, with or without a key:
curl "https://api.ipapi.is/?q=155.136.0.1"