HomeASN LookupAS2856

AS2856 BT-UK-AS British Telecommunications Limited

🇬🇧

Org handle: ORG-BPIS1-RIPE

BTnet UK Regional network

RIPE NCCallocated
Announced Prefixes (BGP)
567total
560 IPv47 IPv6
IPv4 Addresses
Allocated (RIR)16.3M
Announced (BGP)18.5M
IPv6 Addresses
Allocated (RIR)1×10³¹
Announced (BGP)1×10³¹
Prefix Limit (IPv4)
20,000
Prefix Limit (IPv6)
50
Country
🇬🇧 GB
RIR
RIPE NCC
Status
allocated
Allocated
1993-12-22

Routing hygiene

Score 30/100 · Medium risk
RPKI ROA coverage
69.1%
7 prefixes RPKI invalid
IRR route objects
95.6%
14 prefixes registered for another origin
Hijack signals
7
2 announced against others' ROAs, 5 own announced by others
Upstreams
3
diversity 2/100
  • 31% of announced prefixes (175 of 567) have no valid ROA, 7 of them RPKI invalid
  • Routes concentrated on one upstream (99% of routes)
  • Announces 2 prefixes that RPKI assigns to another network (possible hijack or misconfiguration)
  • 7 prefixes registered in IRR route objects for another active network and not authorized by a ROA

Based on 567 announced prefixes, updated daily (2026-10-23). How the score works · RPKI explained

Listed on the threat map (2026-10-23)

Large hosting providers appear because attackers rent their servers, not necessarily because of the operator.

Announced Prefixes

(BGP)567
|
Prefix
RPKI
IRR
Last Seen
5.35.192.0/21
 Valid
RIPE
-
5.80.0.0/15
 Valid
RIPE
-
5.81.0.0/16
 Valid
RIPE
-
5.181.136.0/24
No ROA
RIPE
-
9.151.0.0/19
 Valid
RIPE
-
9.151.208.0/20
 Valid
RIPE
-
9.151.248.0/21
 Valid
RIPE
-
9.232.192.0/18
 Valid
RIPE
-
9.233.48.0/20
 Valid
RIPE
-
9.237.96.0/19
 Valid
RIPE
-
1-10 of 567
1 / 57

Allocated Prefixes

(RIR)341
Prefix
Country
RIR
Status
5.35.192.0/21🇺🇸 USRIPENCCallocated
5.80.0.0/15🇬🇧 GBRIPENCCallocated
5.81.0.0/16🇬🇧 GBRIPEassigned
9.151.0.0/19🇬🇧 GBRIPEassigned
9.151.208.0/20🇬🇧 GBRIPEassigned
9.151.248.0/21🇬🇧 GBRIPEassigned
9.232.192.0/18🇬🇧 GBRIPEassigned
9.233.48.0/20🇬🇧 GBRIPEassigned
9.237.96.0/19🇬🇧 GBRIPEassigned
9.237.128.0/18🇬🇧 GBRIPEassigned
1-10 of 341
1 / 35

All 567 announced prefixes of AS2856 →

Downstream Customers(6)

ASNName
AS9011🇬🇧The Patent Office
AS13447🇺🇸QYRUS-INC - QYRUS INC.
AS15248🇺🇸METASWITCH-AS1 - Metaswitch Networks Corp.
AS197545🇬🇧Era4-ASN Era4 Limited
AS200167🇬🇧excellondon London International Exhibition Centre PLC
AS202907🇬🇧ATOMICIT Atomic IT Limited

BGP Neighbours

(seen in AS paths)

Upstreams (5)

Networks AS2856 hands its own prefixes to: transit providers, or peers at an exchange.

  • AS5400BT British Telecommunications Limited559
  • AS6461Zayo Bandwidth4
  • AS6204ZET NET INTERKVM HOST2
  • AS8966Etisalat EMIRATES TELECOMMUNICATIONS GROUP COMPANY (ETISALAT GROUP) PJSC1
  • AS25180EXPONENTIAL E Exponential E1

Downstreams (100 of 134)

Networks whose own prefixes AS2856 passes on: usually its customers.

  • AS6871Plusnet British Telecommunications Limited64
  • AS2134GSVNET Santander Global Technology And Operations, S.L17
  • AS54113Fastly16
  • AS49318ARC UK TELEFONICA TECH UK MANAGED SERVICES14
  • AS21369SEMA UK Atos IT Services UK13
  • AS20705HSBC UK HSBC Bank Plc11
  • AS12440AS12440 Hughes Network Systems9
  • AS15248Metaswitch Networks9
  • AS3573Accenture LLP8
  • AS25049STASCO UK Shell Information Technology International B.V8
  • AS12222Akamai Technologies7
  • AS14931The St. Paul Travelers Companies6
  • AS14630Invesco Group Services5
  • AS28863Thales SCS Thales UK Limited5
  • AS199675WGSLEDC Willis Group Services5
  • AS206237BARCLAYS BPS Barclays Bank PLC5
  • AS21301UK NATWEST AS21301 Natwest Markets PLC4
  • AS36224HCL AMERICA4
  • AS39550KPMG UK LLP KPMG LLP4
  • AS57002WHORGLTD William Hill Organization4
  • AS212329NETCRAFT4
  • AS8435LBG INTERNET EDGE Lloyds Banking Group PLC3
  • AS13205British Telecommunications Limited3
  • AS16525KBR3
  • AS35707Scottish Power PLC Scottish Power UK PLC3
  • AS39552AHR WBA (IT Services) International Limited3
  • AS50203UK Reynolds ASN Reynolds And Reynolds Limited3
  • AS197545Era4 ASN Era4 Limited3
  • AS204550Continental Limited3
  • AS205114Wrtgltd The WEST Retail Group LImited3
  • AS205693Dvla Driver & Vehicle Licensing Agency3
  • AS211389Briantbroadband Briant Broadband Limited3
  • AS212565SPECSAVERS Optical Group Limited3
  • AS213867TENERITY LIMITED3
  • AS394731Canadian Natural Resources Limited3
  • AS3738State Street Bank And Trust Company2
  • AS9011The Patent Office2
  • AS10235National Australia Bank Limited2
  • AS14766Magnetar Capital2
  • AS15141Bausch & Lomb2
  • AS15499GECITS EU Computacenter Management Trading Computacenter & .OHG2
  • AS15865ELLIOTT UK Elliott Advisors UK ()2
  • AS16839SERVICENOW2
  • AS17903Cognizant Technology Solutions India Pvt2
  • AS19428Phillips 66 Company2
  • AS21470SWISP South West Communications Group2
  • AS22775Moore Capital Management2
  • AS24775AS24775 Qinetiq Limited2
  • AS25421JOHN LEWIS John Lewis Plc2
  • AS29033ECKOH UK Limited2
  • AS33981TSYS Total System Services Processing Europe Limited2
  • AS41570SSVC BFBS2
  • AS43259LEIDOS UK Leidos Innovations UK2
  • AS44371PPN Paypoint Network Limited2
  • AS48549BRINGOGROUP Bringo Group2
  • AS48688Thales UK Thales UK2
  • AS60962BZ Foreign And Commonwealth Office2
  • AS63399Dialpad2
  • AS197409OPERATIVE GROUP Operative Group Limited2
  • AS198386ONI THRIVE OPERATIONS LIMITED2
  • AS201536SANDYXHOSTING SANDYX SYSTEMS LIMITED2
  • AS202907ATOMICIT Atomic IT Limited2
  • AS206024Far UK DualHoming RELX GROUP PLC2
  • AS209761NECS North Of England Commissioning Support Unit2
  • AS211077HO LECN DC01 UK Home Office (The Secretary Of State For The Home Department)2
  • AS218625COMMUNICATION DYNAMICS Communication Dynamics2
  • AS395959XEROX CORPORATION2
  • AS72Schlumberger Limited1
  • AS2535BP America1
  • AS2559VISA INTERNATIONAL SERVICE ASSOCIATION1
  • AS7358The Dun & Bradstreet Corporation1
  • AS8698NATIONWIDE BUILDING SOCIETY1
  • AS11528Photronics1
  • AS11939THE MATHWORKS1
  • AS13447QYRUS1
  • AS17274Robert W. Baird & . Incorporated1
  • AS19239KLA Corporation1
  • AS19305Transaction Network Services1
  • AS19812BT Americas1
  • AS20163Sunrise Medical1
  • AS21054UK NATWEST AS21054 Natwest Markets PLC1
  • AS21110LADBROKES UK Entain Corporate Services Limited1
  • AS21218EBCGROUP EBC Group (UK)1
  • AS21758Modine Manufacturing Company1
  • AS25050BACS VOCALINK1
  • AS25343COVENTRY University1
  • AS29888Unum Group1
  • AS30058FDCservers.Net1
  • AS33001Cravath, Swaine & Moore LLP1
  • AS33127Integrated Systems1
  • AS33442Zebra Technologies Corporation1
  • AS33680TELEPERFORMANCE USA1
  • AS33879FORTHS PORTS PLC Forth Ports Public Limited Company1
  • AS34344THE PORT OF TILBURY LONDON Port Of Tilbury London1
  • AS35350SCHWARZ PHARMA UCB Pharma S.A1
  • AS38191Infosys Technologies1
  • AS38936HMUK Herman Miller1
  • AS41021EBYR HOWDEN Ebuyer UK Limited1
  • AS41373BT Plc NATIONAL HEALTH SERVICE1
  • AS41380ALD Automotive1

Other adjacent networks (3)

Adjacent to AS2856 in the transit part of AS paths: peers, providers or customers.

  • AS28690ING DIRECT UK Barclays Bank PLC19
  • AS60068CDN77 Datacamp Limited10
  • AS9002RETN Limited1
ASPA
No ASPA0 upstreams, 6 downstreams
Listed as Upstream Provider by
6 ASNs
View full ASPA details →
Abuse Contact
External Links
RIPE WhoisRIPEstat

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API
Open
GEThttps://api.ipctl.io/v1/asn/2856

Returns ASN details, announced prefixes, and BGP routing data.

curl -s "https://api.ipctl.io/v1/asn/2856" | jq