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

AS2856 — BT-UK-AS

British Telecommunications PLC

AS2856 is a major transit provider operated by British Telecommunications PLC, established in the United Kingdom in 2002. The network announces a whopping 14.8 million IPv4 addresses (0.40% of routable IPv4 space), including a /10. Supports IPv6.

  • 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
March 04, 2026

Prefix Summary

IPv4 Prefixes (raw / aggregated)
392 / 317
IPv6 Prefixes (raw / aggregated)
7 / 5
IPv4 Addresses
14 832 896
Largest IPv4 Prefix
/10 (4 194 304 addresses)
Largest IPv6 Prefix
/25
Geolocated Countries
🇬🇧 GB (392 IPs), 🇦🇺 AU (17 IPs), 🇺🇸 US (66 IPs), 🇩🇪 DE, 🇳🇱 NL, 🇧🇪 BE, 🇨🇦 CA, 🇸🇨 SC, 🇪🇸 ES, 🇫🇷 FR, 🇮🇪 IE, 🇳🇴 NO, 🇨🇭 CH
Prefix Changed
March 04, 2026

Reputation

Reputation
Good — 97 flagged IPs out of 14 832 896 total (0.00%)
Open Proxies
2 known open proxies in this network

Connectivity Summary

Upstream Providers
2 upstream autonomous systems providing transit
Peers
83 autonomous systems exchanging traffic without transit fees
Downstream Customers
154 downstream autonomous systems buying transit
Degree
241 unique BGP neighbors (providers + customers + peers)
Reach
162 — customer cone size measuring network influence
Degree Rank
#539
Reach Rank
#877

Upstream Providers (2)

Prefix Lists

IPv4 Prefixes (392 total)

  • 86.128.0.0/10 (4 194 304 addresses)
  • 81.128.0.0/11 (2 097 152 addresses)
  • 31.64.0.0/12 (1 048 576 addresses)
  • 109.144.0.0/12 (1 048 576 addresses)
  • 217.32.0.0/12 (1 048 576 addresses)
  • 31.48.0.0/13 (524 288 addresses)
  • 31.112.0.0/13 (524 288 addresses)
  • 95.144.0.0/13 (524 288 addresses)
  • 31.100.0.0/14 (262 144 addresses)
  • 31.120.0.0/14 (262 144 addresses)
  • 147.148.0.0/14 (262 144 addresses)
  • 194.72.0.0/14 (262 144 addresses)
  • 213.120.0.0/14 (262 144 addresses)
  • 5.80.0.0/15 (131 072 addresses)
  • 31.90.0.0/15 (131 072 addresses)
  • 31.92.0.0/15 (131 072 addresses)
  • 31.106.0.0/15 (131 072 addresses)
  • 31.126.0.0/15 (131 072 addresses)
  • 46.68.0.0/15 (131 072 addresses)
  • 62.6.0.0/15 (131 072 addresses)
  • 109.180.0.0/15 (131 072 addresses)
  • 31.94.0.0/16 (65 536 addresses)
  • 31.96.0.0/16 (65 536 addresses)
  • 31.104.0.0/16 (65 536 addresses)
  • 31.124.0.0/16 (65 536 addresses)
  • 51.14.0.0/16 (65 536 addresses)
  • 62.172.0.0/16 (65 536 addresses)
  • 62.239.0.0/16 (65 536 addresses)
  • 91.111.0.0/16 (65 536 addresses)
  • 109.249.0.0/16 (65 536 addresses)
  • 132.146.0.0/16 (65 536 addresses)
  • 147.152.0.0/16 (65 536 addresses)
  • 149.254.0.0/16 (65 536 addresses)
  • 165.120.0.0/16 (65 536 addresses)
  • 193.113.0.0/16 (65 536 addresses)
  • 195.99.0.0/16 (65 536 addresses)
  • 195.171.0.0/16 (65 536 addresses)
  • 212.140.0.0/16 (65 536 addresses)
  • 213.1.0.0/16 (65 536 addresses)
  • 51.230.0.0/17 (32 768 addresses)
  • 144.87.128.0/18 (16 384 addresses)
  • 213.205.192.0/18 (16 384 addresses)
  • 84.23.0.0/19 (8 192 addresses)
  • 159.180.96.0/19 (8 192 addresses)
  • 193.38.192.0/19 (8 192 addresses)
  • 194.102.0.0/19 (8 192 addresses)
  • 195.218.32.0/19 (8 192 addresses)
  • 212.82.0.0/19 (8 192 addresses)
  • 85.88.224.0/20 (4 096 addresses)
  • 144.87.16.0/20 (4 096 addresses)

IPv6 Prefixes (7 total)

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