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 9 IPv4 prefixes with 68,352 addresses, which makes it the 3,104th largest of 82,283 active autonomous systems by IPv4 space.
IPv4 addresses68,352in 9 prefixes
IPv6 prefixes0none
Size rank#3,104of 82,283 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
9 prefixes · 68,352 addresses| Network | Addresses | First – last address |
|---|---|---|
| 155.136.0.0/16 | 65,536 | 155.136.0.0 – 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 |
155.136.0.0/16 155.136.60.0/22 155.136.60.0/24 155.136.61.0/24 155.136.62.0/24 155.136.63.0/24 155.136.197.0/24 155.136.202.0/24 155.136.203.0/24
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"