Autonomous system detail

AS2856

Announced

Operated by BT-UK-AS British Telecommunications Limited.

Summary

// analyst note
A 2856 IP is typically a UK BT consumer/business broadband subscriber; BT's international transit sits under AS5400.
// security note
UK residential/business eyeball + backbone.
IPv4 prefixes
495
~18.4M addresses
IPv6 prefixes
7
announced
Peer networks
234
23 up · 216 down
IANA block
2830-2879
Assigned by RIPE NCC
[ 01 ] — Context

About this ASN.

Updated  ·  Confidence: High

AS2856 is the UK regional autonomous system of British Telecommunications PLC, the incumbent UK operator, registered under RIPE since December 1993. The RIPE record labels it the "BTnet UK Regional network," and it is a mixed eyeball-and-backbone ASN: a large UK residential and business access network combined with national backbone capacity, classified in PeeringDB as an NSP. Community route-intelligence tools rank it among the top networks by estimated eyeballs (roughly #37 globally and #1 in the UK) and around #36 by originated IPv4 space; it announces a few hundred IPv4 prefixes (about 13.7–13.8 million addresses) but a strikingly small IPv6 set (single digits), reflecting limited IPv6 origination on this particular ASN. Its route hygiene is clean — in the observed view every originated prefix was RPKI-valid with no invalids. BT's international transit and global carrier role sit on a separate ASN, AS5400 (British Telecommunications International), which is also an upstream feeding the UK regional network; the group additionally includes AS8968 (BT Italia), and the AS-BTGB set ties the family together. Traffic on AS2856 is predominantly inbound at a few Tbps. For triage, a 2856 address is typically a UK BT consumer or business broadband subscriber, with the usual residential dynamic-IP caveat.

Operator
British Telecommunications PLC (RIPE org ORG-BPIS1-RIPE) [Confirmed] — RIPE RDAP/WHOIS
Country / RIR
UK, RIPE [Confirmed] — RIPE RDAP
Allocated
1993-12-22 [Confirmed] — RIPE RDAP / DNSlytics
Org status
active; part of BT Group plc — bt.com

Security/abuse context

UK residential/business eyeball + backbone. Residential dynamic-IP reassignment caveat. RPKI all valid (~333 valid / 0 invalid observed). No carrier-specific abuse listing of note as of 2026-06-04 — bgp.he.net

Network & routing

Network type
mixed — large UK ISP-eyeball (BTnet) + national backbone (PeeringDB NSP) [Confirmed] — PeeringDB + RIPE aut-num
Size
~324–483 IPv4 prefixes originated (~13.7–13.8M addrs), ~3–7 IPv6 (very small IPv6); community ranks ~#37 eyeballs globally / ~#1 UK / ~#36 originated IPv4 — RIPEstat (483 v4 / 7 v6, 2026-05-21), bgp.he.net / bgp.tools
Routing/peering
~184–252 peers; ~2 upstreams incl. sibling AS5400 (BT International); traffic 1–5 Tbps, mostly inbound — RIPE import policy, peeringdb.com
Notable usage
BTnet UK regional access + national backbone — bt.net
Related ASNs
AS5400 (British Telecommunications International — international/transit ASN), AS8968 (BT Italia); as-set AS-BTGB
Analyst note
A 2856 IP is typically a UK BT consumer/business broadband subscriber; BT's international transit sits under AS5400.
[ 02 ] — Announced prefixes

What this network routes.

502 prefixes total · RIPEstat data · cached, not real-time
// IPv4 prefixes495
  1. 86.128.0.0/10/10
  2. 81.128.0.0/11/11
  3. 86.128.0.0/11/11
  4. 86.128.0.0/12/12
  5. 217.32.0.0/12/12
  6. 109.144.0.0/12/12
  7. 81.128.0.0/12/12
  8. 31.48.0.0/13/13
  9. 95.144.0.0/13/13
  10. 31.100.0.0/14/14
  11. 31.112.0.0/14/14
  12. 194.72.0.0/14/14
  13. 147.148.0.0/14/14
  14. 31.116.0.0/14/14
  15. 213.120.0.0/14/14
  16. 31.90.0.0/15/15
  17. 109.180.0.0/15/15
  18. 31.92.0.0/15/15
  19. 31.126.0.0/15/15
  20. 31.122.0.0/15/15
  21. 5.80.0.0/15/15
  22. 31.106.0.0/15/15
  23. 46.68.0.0/15/15
  24. 31.94.0.0/16/16
  25. 31.117.0.0/16/16
  26. 31.124.0.0/16/16
  27. 51.14.0.0/16/16
  28. 31.116.0.0/16/16
  29. 62.6.0.0/16/16
  30. 62.7.0.0/16/16
  31. 31.120.0.0/16/16
  32. 212.140.0.0/16/16
  33. 213.1.0.0/16/16
  34. 91.111.0.0/16/16
  35. 31.96.0.0/16/16
  36. 147.152.0.0/16/16
  37. 165.120.0.0/16/16
  38. 31.118.0.0/16/16
  39. 31.104.0.0/16/16
  40. 62.172.0.0/16/16
  41. 132.146.0.0/16/16
  42. 195.99.0.0/16/16
  43. 195.171.0.0/16/16
  44. 31.119.0.0/16/16
  45. 193.113.0.0/16/16
  46. 5.81.0.0/16/16
  47. 31.121.0.0/16/16
  48. 149.254.0.0/16/16
  49. 62.239.0.0/16/16
  50. 109.249.0.0/16/16
  51. 144.87.128.0/18/18
  52. 9.237.128.0/18/18
  53. 213.205.192.0/18/18
  54. 9.232.192.0/18/18
  55. 212.82.0.0/19/19
  56. 9.237.192.0/19/19
  57. 9.151.0.0/19/19
  58. 194.102.0.0/19/19
  59. 9.237.96.0/19/19
  60. 84.23.0.0/19/19
  61. 193.38.192.0/19/19
  62. 195.218.32.0/19/19
  63. 159.180.96.0/19/19
  64. 51.230.96.0/20/20
  65. 51.230.0.0/20/20
  66. 85.88.224.0/20/20
  67. 193.37.160.0/20/20
  68. 144.87.16.0/20/20
  69. 9.151.208.0/20/20
  70. 213.205.208.0/20/20
  71. 217.15.64.0/20/20
  72. 9.233.48.0/20/20
  73. 51.230.112.0/20/20
  74. 51.230.64.0/20/20
  75. 51.230.48.0/20/20
  76. 193.35.128.0/20/20
  77. 51.230.32.0/20/20
  78. 51.230.80.0/20/20
  79. 51.230.16.0/20/20
  80. 188.172.168.0/21/21
  81. 178.78.120.0/21/21
  82. 161.104.0.0/21/21
  83. 144.87.24.0/21/21
  84. 87.237.16.0/21/21
  85. 5.35.192.0/21/21
  86. 194.169.32.0/21/21
  87. 144.87.0.0/21/21
  88. 94.72.248.0/21/21
  89. 188.172.160.0/21/21
  90. 178.78.112.0/21/21
  91. 82.108.32.0/21/21
  92. 9.151.248.0/21/21
  93. 83.245.16.0/21/21
  94. 82.38.56.0/22/22
  95. 151.240.192.0/22/22
  96. 147.189.68.0/22/22
  97. 81.161.52.0/22/22
  98. 85.204.160.0/22/22
  99. 213.249.188.0/22/22
  100. 151.240.184.0/22/22
  101. 178.95.60.0/22/22
  102. 82.108.52.0/22/22
  103. 46.248.120.0/22/22
  104. 151.240.200.0/22/22
  105. 151.241.200.0/22/22
  106. 178.78.108.0/22/22
  107. 185.68.200.0/22/22
  108. 151.241.196.0/22/22
  109. 37.97.112.0/22/22
  110. 178.94.244.0/22/22
  111. 82.41.112.0/22/22
  112. 82.108.44.0/22/22
  113. 37.143.0.0/22/22
  114. 185.90.32.0/22/22
  115. 151.244.80.0/22/22
  116. 94.232.100.0/22/22
  117. 151.241.52.0/22/22
  118. 82.108.68.0/22/22
  119. 78.105.136.0/22/22
  120. 164.38.16.0/22/22
  121. 217.217.36.0/22/22
  122. 72.9.180.0/22/22
  123. 151.241.188.0/22/22
  124. 46.248.96.0/22/22
  125. 151.244.204.0/22/22
  126. 193.38.192.0/22/22
  127. 82.108.140.0/22/22
  128. 178.92.112.0/22/22
  129. 51.146.252.0/22/22
  130. 151.240.196.0/22/22
  131. 212.212.16.0/22/22
  132. 151.240.188.0/22/22
  133. 164.38.184.0/22/22
  134. 144.87.28.0/22/22
  135. 178.93.104.0/22/22
  136. 51.194.100.0/22/22
  137. 164.38.120.0/22/22
  138. 151.245.208.0/22/22
  139. 151.245.204.0/22/22
  140. 212.134.208.0/22/22
  141. 82.108.116.0/22/22
  142. 51.146.44.0/22/22
  143. 178.92.180.0/22/22
  144. 144.87.24.0/22/22
  145. 151.241.180.0/22/22
  146. 64.205.136.0/22/22
  147. 51.146.136.0/22/22
  148. 167.148.60.0/22/22
  149. 151.241.192.0/22/22
  150. 51.146.128.0/22/22
  151. 212.134.124.0/22/22
  152. 145.79.172.0/22/22
  153. 151.241.56.0/22/22
  154. 217.217.56.0/22/22
  155. 151.240.180.0/22/22
  156. 194.32.20.0/22/22
  157. 151.244.208.0/22/22
  158. 147.189.76.0/22/22
  159. 212.134.224.0/22/22
  160. 193.35.220.0/22/22
  161. 82.108.4.0/22/22
  162. 15.145.20.0/22/22
  163. 64.205.144.0/22/22
  164. 147.78.68.0/22/22
  165. 82.108.92.0/22/22
  166. 217.217.60.0/22/22
  167. 212.134.164.0/22/22
  168. 151.245.80.0/22/22
  169. 151.241.184.0/22/22
  170. 193.187.140.0/22/22
  171. 151.241.60.0/22/22
  172. 193.36.80.0/22/22
  173. 83.245.24.0/22/22
  174. 45.149.170.0/23/23
  175. 51.194.36.0/23/23
  176. 142.205.162.0/23/23
  177. 213.169.196.0/23/23
  178. 89.39.172.0/23/23
  179. 62.192.124.0/23/23
  180. 82.108.152.0/23/23
  181. 209.101.8.0/23/23
  182. 89.145.172.0/23/23
  183. 159.253.66.0/23/23
  184. 144.177.74.0/23/23
  185. 82.108.102.0/23/23
  186. 50.118.154.0/23/23
  187. 185.177.64.0/23/23
  188. 213.190.16.0/23/23
  189. 193.35.160.0/23/23
  190. 213.169.202.0/23/23
  191. 193.35.158.0/23/23
  192. 46.248.104.0/23/23
  193. 152.114.222.0/23/23
  194. 94.26.64.0/23/23
  195. 157.236.254.0/23/23
  196. 148.253.220.0/23/23
  197. 192.177.94.0/23/23
  198. 152.114.220.0/23/23
  199. 82.136.54.0/23/23
  200. 79.139.52.0/23/23
  201. 213.190.18.0/23/23
  202. 178.78.106.0/23/23
  203. 91.236.216.0/23/23
  204. 23.230.82.0/23/23
  205. 178.212.56.0/23/23
  206. 85.88.240.0/23/23
  207. 82.108.88.0/23/23
  208. 87.86.24.0/23/23
  209. 193.36.78.0/23/23
  210. 193.38.192.0/23/23
  211. 31.130.240.0/23/23
  212. 205.239.40.0/23/23
  213. 46.248.102.0/23/23
  214. 217.31.10.0/23/23
  215. 79.139.54.0/23/23
  216. 45.149.168.0/23/23
  217. 193.38.194.0/23/23
  218. 149.117.130.0/24/24
  219. 164.38.32.0/24/24
  220. 193.23.32.0/24/24
  221. 132.153.254.0/24/24
  222. 37.44.231.0/24/24
  223. 157.236.255.0/24/24
  224. 45.149.7.0/24/24
  225. 164.38.31.0/24/24
  226. 194.246.78.0/24/24
  227. 156.146.3.0/24/24
  228. 23.27.107.0/24/24
  229. 213.209.146.0/24/24
  230. 86.38.93.0/24/24
  231. 193.37.142.0/24/24
  232. 192.8.149.0/24/24
  233. 23.27.37.0/24/24
  234. 216.120.189.0/24/24
  235. 62.244.36.0/24/24
  236. 86.110.57.0/24/24
  237. 163.5.222.0/24/24
  238. 86.38.244.0/24/24
  239. 194.32.29.0/24/24
  240. 84.55.17.0/24/24
  241. 132.244.79.0/24/24
  242. 212.134.54.0/24/24
  243. 213.209.149.0/24/24
  244. 132.153.250.0/24/24
  245. 138.108.94.0/24/24
  246. 147.90.115.0/24/24
  247. 198.232.43.0/24/24
  248. 195.130.13.0/24/24
  249. 82.153.85.0/24/24
  250. 164.38.33.0/24/24
  251. 77.90.151.0/24/24
  252. 163.5.98.0/24/24
  253. 23.27.105.0/24/24
  254. 86.54.81.0/24/24
  255. 132.153.253.0/24/24
  256. 91.90.127.0/24/24
  257. 207.180.43.0/24/24
  258. 94.125.18.0/24/24
  259. 194.70.94.0/24/24
  260. 147.90.32.0/24/24
  261. 51.64.34.0/24/24
  262. 62.244.12.0/24/24
  263. 62.244.29.0/24/24
  264. 132.153.252.0/24/24
  265. 84.55.22.0/24/24
  266. 195.130.14.0/24/24
  267. 82.140.134.0/24/24
  268. 84.46.194.0/24/24
  269. 194.60.138.0/24/24
  270. 192.65.222.0/24/24
  271. 217.31.9.0/24/24
  272. 159.197.44.0/24/24
  273. 163.5.115.0/24/24
  274. 192.65.225.0/24/24
  275. 159.197.45.0/24/24
  276. 166.88.32.0/24/24
  277. 192.65.221.0/24/24
  278. 195.104.240.0/24/24
  279. 164.38.149.0/24/24
  280. 23.26.70.0/24/24
  281. 82.153.238.0/24/24
  282. 84.46.177.0/24/24
  283. 45.39.116.0/24/24
  284. 82.140.170.0/24/24
  285. 148.252.7.0/24/24
  286. 83.223.153.0/24/24
  287. 192.65.224.0/24/24
  288. 62.244.41.0/24/24
  289. 151.246.145.0/24/24
  290. 164.38.197.0/24/24
  291. 78.105.97.0/24/24
  292. 163.5.37.0/24/24
  293. 192.65.226.0/24/24
  294. 23.26.192.0/24/24
  295. 51.64.35.0/24/24
  296. 91.102.189.0/24/24
  297. 51.146.235.0/24/24
  298. 86.38.65.0/24/24
  299. 151.242.42.0/24/24
  300. 85.235.123.0/24/24
  301. 195.130.11.0/24/24
  302. 194.227.120.0/24/24
  303. 194.132.25.0/24/24
  304. 62.244.37.0/24/24
  305. 192.65.223.0/24/24
  306. 164.38.134.0/24/24
  307. 193.33.199.0/24/24
  308. 82.38.9.0/24/24
  309. 195.88.20.0/24/24
  310. 194.227.72.0/24/24
  311. 37.44.229.0/24/24
  312. 86.38.233.0/24/24
  313. 195.36.106.0/24/24
  314. 86.38.68.0/24/24
  315. 194.132.24.0/24/24
  316. 147.90.127.0/24/24
  317. 164.38.148.0/24/24
  318. 164.134.137.0/24/24
  319. 82.153.190.0/24/24
  320. 151.242.24.0/24/24
  321. 185.58.165.0/24/24
  322. 91.142.128.0/24/24
  323. 151.246.239.0/24/24
  324. 82.39.173.0/24/24
  325. 194.36.135.0/24/24
  326. 194.32.31.0/24/24
  327. 164.38.34.0/24/24
  328. 62.244.56.0/24/24
  329. 95.173.59.0/24/24
  330. 91.90.125.0/24/24
  331. 149.254.1.0/24/24
  332. 193.138.107.0/24/24
  333. 185.230.15.0/24/24
  334. 5.181.136.0/24/24
  335. 166.88.17.0/24/24
  336. 86.38.118.0/24/24
  337. 147.90.36.0/24/24
  338. 185.149.6.0/24/24
  339. 23.27.103.0/24/24
  340. 62.244.11.0/24/24
  341. 195.35.123.0/24/24
  342. 77.90.135.0/24/24
  343. 91.230.16.0/24/24
  344. 194.60.139.0/24/24
  345. 185.230.13.0/24/24
  346. 51.149.19.0/24/24
  347. 166.88.200.0/24/24
  348. 163.5.217.0/24/24
  349. 216.165.88.0/24/24
  350. 194.227.73.0/24/24
  351. 164.38.12.0/24/24
  352. 163.5.249.0/24/24
  353. 193.84.142.0/24/24
  354. 164.134.138.0/24/24
  355. 51.64.32.0/24/24
  356. 77.90.138.0/24/24
  357. 77.94.224.0/24/24
  358. 132.153.247.0/24/24
  359. 86.38.67.0/24/24
  360. 194.189.44.0/24/24
  361. 91.230.40.0/24/24
  362. 132.153.245.0/24/24
  363. 91.102.191.0/24/24
  364. 89.117.235.0/24/24
  365. 185.128.205.0/24/24
  366. 193.35.197.0/24/24
  367. 23.27.104.0/24/24
  368. 45.39.188.0/24/24
  369. 194.155.58.0/24/24
  370. 192.53.46.0/24/24
  371. 192.8.112.0/24/24
  372. 164.38.156.0/24/24
  373. 23.26.117.0/24/24
  374. 194.60.136.0/24/24
  375. 37.230.61.0/24/24
  376. 46.68.66.0/24/24
  377. 23.27.108.0/24/24
  378. 86.38.193.0/24/24
  379. 86.38.63.0/24/24
  380. 164.134.136.0/24/24
  381. 192.65.219.0/24/24
  382. 193.36.243.0/24/24
  383. 82.153.179.0/24/24
  384. 86.38.86.0/24/24
  385. 132.153.3.0/24/24
  386. 23.27.32.0/24/24
  387. 192.152.14.0/24/24
  388. 91.102.190.0/24/24
  389. 23.27.34.0/24/24
  390. 132.153.248.0/24/24
  391. 89.117.198.0/24/24
  392. 37.44.230.0/24/24
  393. 77.90.184.0/24/24
  394. 89.117.203.0/24/24
  395. 163.5.67.0/24/24
  396. 148.252.3.0/24/24
  397. 82.153.181.0/24/24
  398. 193.111.18.0/24/24
  399. 84.46.190.0/24/24
  400. 82.140.143.0/24/24
  401. 86.38.56.0/24/24
  402. 23.27.40.0/24/24
  403. 195.130.6.0/24/24
  404. 194.35.183.0/24/24
  405. 151.247.220.0/24/24
  406. 166.88.18.0/24/24
  407. 51.230.255.0/24/24
  408. 86.38.123.0/24/24
  409. 132.153.249.0/24/24
  410. 82.153.33.0/24/24
  411. 163.5.122.0/24/24
  412. 194.32.207.0/24/24
  413. 164.38.196.0/24/24
  414. 84.46.181.0/24/24
  415. 51.149.18.0/24/24
  416. 89.117.183.0/24/24
  417. 94.125.17.0/24/24
  418. 40.27.72.0/24/24
  419. 23.27.102.0/24/24
  420. 193.39.141.0/24/24
  421. 164.134.135.0/24/24
  422. 192.12.73.0/24/24
  423. 23.27.39.0/24/24
  424. 163.5.208.0/24/24
  425. 77.90.153.0/24/24
  426. 80.81.58.0/24/24
  427. 164.134.134.0/24/24
  428. 212.148.1.0/24/24
  429. 152.114.196.0/24/24
  430. 164.38.2.0/24/24
  431. 91.227.78.0/24/24
  432. 23.27.106.0/24/24
  433. 194.59.188.0/24/24
  434. 79.132.65.0/24/24
  435. 82.140.138.0/24/24
  436. 23.27.36.0/24/24
  437. 205.239.42.0/24/24
  438. 109.205.158.0/24/24
  439. 194.36.68.0/24/24
  440. 212.134.46.0/24/24
  441. 62.244.43.0/24/24
  442. 132.153.244.0/24/24
  443. 23.230.242.0/24/24
  444. 193.32.46.0/24/24
  445. 164.134.1.0/24/24
  446. 79.132.64.0/24/24
  447. 195.130.15.0/24/24
  448. 87.232.114.0/24/24
  449. 151.247.245.0/24/24
  450. 83.223.154.0/24/24
  451. 192.65.227.0/24/24
  452. 94.125.19.0/24/24
  453. 195.130.3.0/24/24
  454. 77.90.145.0/24/24
  455. 23.230.252.0/24/24
  456. 193.36.240.0/24/24
  457. 147.90.55.0/24/24
  458. 50.117.7.0/24/24
  459. 192.65.228.0/24/24
  460. 198.178.235.0/24/24
  461. 94.125.16.0/24/24
  462. 77.90.164.0/24/24
  463. 84.46.191.0/24/24
  464. 195.130.12.0/24/24
  465. 213.209.150.0/24/24
  466. 193.36.80.0/24/24
  467. 212.134.52.0/24/24
  468. 193.195.138.0/24/24
  469. 194.60.137.0/24/24
  470. 193.32.48.0/24/24
  471. 86.38.148.0/24/24
  472. 132.153.251.0/24/24
  473. 40.27.28.0/24/24
  474. 23.26.131.0/24/24
  475. 23.26.108.0/24/24
  476. 82.153.88.0/24/24
  477. 87.76.183.0/24/24
  478. 193.111.19.0/24/24
  479. 23.27.35.0/24/24
  480. 23.27.38.0/24/24
  481. 23.27.33.0/24/24
  482. 195.182.62.0/24/24
  483. 50.117.51.0/24/24
  484. 132.153.246.0/24/24
  485. 151.243.254.0/24/24
  486. 157.236.254.0/24/24
  487. 84.46.188.0/24/24
  488. 151.247.231.0/24/24
  489. 143.223.132.0/24/24
  490. 84.46.183.0/24/24
  491. 193.36.253.0/24/24
  492. 62.244.45.0/24/24
  493. 159.197.13.0/24/24
  494. 51.241.201.0/24/24
  495. 51.241.3.0/24/24
// IPv6 prefixes7
  1. 2a00:2380::/25/25
  2. 2a01:4c8::/29/29
  3. 2a02:ee80:4176::/47/47
  4. 2a03:1e82:90ff::/48/48
  5. 2a01:4c8:f401::/48/48
  6. 2a01:4c8:f400::/48/48
  7. 2001:4878:c259::/48/48
[ 03 ] — Notable peers & upstreams

Who it talks to.

234 observed neighbours
// Notable connectionsTop 20 of 234
ASNOperatorRole
AS5400 BT British Telecommunications Limited upstream
AS9002 RETN-AS RETN Limited upstream
AS13030 INIT7 Init7 (Switzerland) Ltd. upstream
AS6461 ZAYO-6461 - Zayo Bandwidth upstream
AS3303 SWISSCOM Swisscom (Schweiz) AG upstream
AS5405 INTERDOTLINK Inter.link GmbH upstream
AS50304 BLIX Blix Solutions AS upstream
AS60068 CDN77 Datacamp Limited upstream
AS8220 COLT COLT Technology Services Group Limited upstream
AS4455 BSO IX Reach Ltd upstream
AS215638 AS-CILIX-LIMITED Cilix Limited upstream
AS6204 ZET-NET INTERKVM HOST SRL upstream
AS61049 EXASCALE Exascale Ltd upstream
AS137409 GSLNETWORKS-AS-AP - GSL Networks Pty LTD upstream
AS9009 M247 M247 Europe SRL upstream
AS30844 LIQUID-AS Liquid Telecommunications Ltd upstream
AS1267 ASN-WINDTRE WIND TRE S.P.A. upstream
AS9505 TWGATE-AP - Taiwan Internet Gateway upstream
AS56595 FLUENCY Commsworld Ltd upstream
AS25180 EXPONENTIAL-E-AS Exponential-E Ltd. upstream
Neighbours observed via public BGP collectors; not a complete peering list.