$ query “AS2856” --type=asn → 1 result(s)

AS2856 · BT-UK-AS

British Telecommunications PLC

AS2856 belongs to British Telecommunications PLC and is a major transit provider, registered in the United Kingdom since 2002. The system announces a whopping 13.8 million IPv4 addresses (0.37% of routable IPv4 space), including a /10, and supports IPv6. Its primary geographic footprint is in the United Kingdom, with additional presence in Australia and the United States, and smaller footprints in 12 additional countries. This AS has recently updated its prefix announcements.

  • Top 5% — Top 5% of all autonomous systems by reach and degree
  • Space Overlord — Over 10 million IPv4 addresses

Basic Information

Country
🇬🇧 United Kingdom
Category
Internet Service Provider
Network Role
Major Transit
Data Origin
Authoritative — Metadata from authoritative RIR registry (ARIN, RIPE, APNIC, etc.)
Registered
August 30, 2002
Last Changed
March 04, 2026
Last Seen
April 29, 2026 (active)

Prefix Summary

IPv4 Prefixes (raw / aggregated)
432 / 350
IPv6 Prefixes (raw / aggregated)
7 / 5
IPv4 Addresses
13 817 088
Largest IPv4 Prefix
/10 (4 194 304 addresses)
Largest IPv6 Prefix
/25
Geolocated Countries
🇬🇧 United Kingdom (24 806 064 IPs), 🇦🇺 Australia (1 249 280 IPs), 🇺🇸 United States (43 776 IPs) and 12 more
Prefix Changed
April 29, 2026

Reputation

Reputation
Good — 104 flagged IPs out of 13 817 088 total (0.00%)
Open Proxies
1 known open proxies in this network

Connectivity Summary

Upstream Providers
2 upstreams providing transit
Peers
91 networks exchanging traffic without transit
Downstream Customers
152 downstreams buying transit
Unclassified
3 unclassified BGP neighbors
Degree
248 unique BGP neighbors
Reach
160 networks in customer cone

Upstream Providers (2)

Prefix Lists

IPv4 Prefixes (432 total)

  • 86.128.0.0/10 (4 194 304 addresses (/10 prefix))
  • 81.128.0.0/11 (2 097 152 addresses (/11 prefix))
  • 109.144.0.0/12 (1 048 576 addresses (/12 prefix))
  • 217.32.0.0/12 (1 048 576 addresses (/12 prefix))
  • 31.48.0.0/13 (524 288 addresses (/13 prefix))
  • 95.144.0.0/13 (524 288 addresses (/13 prefix))
  • 31.112.0.0/13 (524 288 addresses (/13 prefix))
  • 213.120.0.0/14 (262 144 addresses (/14 prefix))
  • 194.72.0.0/14 (262 144 addresses (/14 prefix))
  • 147.148.0.0/14 (262 144 addresses (/14 prefix))
  • 31.120.0.0/14 (262 144 addresses (/14 prefix))
  • 31.100.0.0/14 (262 144 addresses (/14 prefix))
  • 109.180.0.0/15 (131 072 addresses (/15 prefix))
  • 62.6.0.0/15 (131 072 addresses (/15 prefix))
  • 5.80.0.0/15 (131 072 addresses (/15 prefix))
  • 31.106.0.0/15 (131 072 addresses (/15 prefix))
  • 46.68.0.0/15 (131 072 addresses (/15 prefix))
  • 31.92.0.0/15 (131 072 addresses (/15 prefix))
  • 31.90.0.0/15 (131 072 addresses (/15 prefix))
  • 31.126.0.0/15 (131 072 addresses (/15 prefix))
  • 165.120.0.0/16 (65 536 addresses (/16 prefix))
  • 62.239.0.0/16 (65 536 addresses (/16 prefix))
  • 31.124.0.0/16 (65 536 addresses (/16 prefix))
  • 147.152.0.0/16 (65 536 addresses (/16 prefix))
  • 212.140.0.0/16 (65 536 addresses (/16 prefix))
  • 62.172.0.0/16 (65 536 addresses (/16 prefix))
  • 91.111.0.0/16 (65 536 addresses (/16 prefix))
  • 149.254.0.0/16 (65 536 addresses (/16 prefix))
  • 31.96.0.0/16 (65 536 addresses (/16 prefix))
  • 31.94.0.0/16 (65 536 addresses (/16 prefix))
  • 213.1.0.0/16 (65 536 addresses (/16 prefix))
  • 195.171.0.0/16 (65 536 addresses (/16 prefix))
  • 51.14.0.0/16 (65 536 addresses (/16 prefix))
  • 109.249.0.0/16 (65 536 addresses (/16 prefix))
  • 193.113.0.0/16 (65 536 addresses (/16 prefix))
  • 132.146.0.0/16 (65 536 addresses (/16 prefix))
  • 195.99.0.0/16 (65 536 addresses (/16 prefix))
  • 31.104.0.0/16 (65 536 addresses (/16 prefix))
  • 51.230.0.0/17 (32 768 addresses (/17 prefix))
  • 144.87.128.0/18 (16 384 addresses (/18 prefix))
  • 213.205.192.0/18 (16 384 addresses (/18 prefix))
  • 194.102.0.0/19 (8 192 addresses (/19 prefix))
  • 193.38.192.0/19 (8 192 addresses (/19 prefix))
  • 195.218.32.0/19 (8 192 addresses (/19 prefix))
  • 212.82.0.0/19 (8 192 addresses (/19 prefix))
  • 84.23.0.0/19 (8 192 addresses (/19 prefix))
  • 159.180.96.0/19 (8 192 addresses (/19 prefix))
  • 193.37.160.0/20 (4 096 addresses (/20 prefix))
  • 85.88.224.0/20 (4 096 addresses (/20 prefix))
  • 193.35.128.0/20 (4 096 addresses (/20 prefix))
  • and 300 more

IPv6 Prefixes (7 total)

  • 2a00:2380::/25
  • 2a01:4c8::/29
  • 2a02:ee80:4176::/47
  • 2001:4878:c259::/48
  • 2a03:1e82:90ff::/48