Autonomous System
AS21301 Natwest Markets PLC
BankingActiveUnited KingdomRIPE
AS21301 (UK-NATWEST-AS21301) is a banking network operated by Natwest Markets PLC in United Kingdom, registered with RIPE. It has 12 IPv4 prefixes with 69,376 addresses, which makes it the 3,053rd largest of 82,132 active autonomous systems by IPv4 space.
IPv4 addresses69,376in 12 prefixes
IPv6 prefixes0none
Size rank#3,053of 82,132 active ASNs
Details
OrganizationNatwest Markets PLC
AS nameUK-NATWEST-AS21301
Websitenatwestmarkets.com
Country United Kingdom (GB)
Network typeBanking
RegistryRIPE
Abuse contactabuse.cz@o2.com
Registered2001-10-24
Last updated2026-04-10
IPv4 prefixes
12 prefixes · 69,376 addresses| Network | Addresses | First – last address |
|---|---|---|
| 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 |
| 155.136.56.0/22 | 1,024 | 155.136.56.0 – 155.136.59.255 |
| 155.136.200.0/23 | 512 | 155.136.200.0 – 155.136.201.255 |
| 155.136.202.0/23 | 512 | 155.136.202.0 – 155.136.203.255 |
| 155.136.56.0/24 | 256 | 155.136.56.0 – 155.136.56.255 |
| 155.136.57.0/24 | 256 | 155.136.57.0 – 155.136.57.255 |
| 155.136.58.0/24 | 256 | 155.136.58.0 – 155.136.58.255 |
| 155.136.59.0/24 | 256 | 155.136.59.0 – 155.136.59.255 |
| 155.136.151.0/24 | 256 | 155.136.151.0 – 155.136.151.255 |
| 155.136.200.0/24 | 256 | 155.136.200.0 – 155.136.200.255 |
| 155.136.201.0/24 | 256 | 155.136.201.0 – 155.136.201.255 |
155.136.0.0/17 155.136.128.0/17 155.136.56.0/22 155.136.200.0/23 155.136.202.0/23 155.136.56.0/24 155.136.57.0/24 155.136.58.0/24 155.136.59.0/24 155.136.151.0/24 155.136.200.0/24 155.136.201.0/24
IPv6 prefixes
No IPv6 prefixes.
Query AS21301 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=AS21301&key=YOUR_API_KEY"Any address in its prefixes resolves to AS21301, with or without a key:
curl "https://api.ipapi.is/?q=155.136.0.1"