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Autonomous systems

AS5400 British Telecommunications PLC

Autonomous system AS5400 (British Telecommunications PLC): 73 IPv4 networks (713,728 addresses) and 10 IPv6 networks, mostly in United Kingdom. Prefix list for firewalls.

AS5400
Organisation
British Telecommunications PLC
Countries (share of addresses)
United Kingdom 34.8% Sweden 20.3% Netherlands 12.7% Germany 11.2% France 4.7% Belgium 4.1% Poland 2.6% Spain 2.1%
IPv4 addresses
713,728
IPv4 networks
73
IPv6 networks
10

IPv4 networks 73

Show 25 more

IPv6 networks 10

Prefix list for a firewall

Ready-made rules to allow or block the whole of AS5400.

What an autonomous system is

An autonomous system (AS) is the set of IP networks run by one organisation under a single routing policy. Providers, hosts and large companies announce their networks to the internet over BGP under their own AS number. With the number you can find all of an organisation’s addresses, for example to allow a service through a firewall or to block traffic from a network.

Network and country data come from DB-IP and are refreshed monthly. The country shows where addresses are used, not where the company is registered.