Consumer ISP
AS6871 British Telecommunications PLCASN lookup: IP ranges, prefixes and network type
AS6871 is the autonomous system number (ASN) announced by British Telecommunications PLC. It announces 78 prefixes, 2,138,367 IPv4 addresses in total. Every address inside those ranges is routed by this operator, which is what makes the number the shortest answer to who runs a given address.
AS6871 at a glance
| Organisation | British Telecommunications PLC |
|---|---|
| Autonomous system | AS6871 |
| Network type | Consumer ISP |
| IPv4 prefixes | 77 |
| IPv6 prefixes | 1 |
| IPv4 addresses | 2,138,367Summed across every announced prefix. IPv6 is not counted; the numbers are meaningless at that scale. |
| In known VPN ranges | 0 of 77 prefixes |
| In known datacenter ranges | 0 of 77 prefixes |
The last two rows are a second opinion, counted against the X4BNet VPN and datacenter range lists rather than read off the operator name. A network with most of its prefixes in the VPN list is carrying anonymised traffic whatever it calls itself.
Sample prefixes
The largest ranges British Telecommunications PLC announces, biggest first. These are a sample and not the full routing table: 78 prefixes do not fit on a page, and the ones worth showing are the ones most traffic comes from.
| Prefix | Family | Addresses |
|---|---|---|
| 31.108.0.0/14 | IPv4 | 262,144 |
| 87.112.0.0/14 | IPv4 | 262,144 |
| 51.6.0.0/15 | IPv4 | 131,072 |
| 84.92.0.0/15 | IPv4 | 131,072 |
| 146.198.0.0/15 | IPv4 | 131,072 |
| 31.125.0.0/16 | IPv4 | 65,536 |
| 51.9.0.0/16 | IPv4 | 65,536 |
| 80.189.0.0/16 | IPv4 | 65,536 |
| 80.229.0.0/16 | IPv4 | 65,536 |
| 91.125.0.0/16 | IPv4 | 65,536 |
| 143.159.0.0/16 | IPv4 | 65,536 |
| 146.90.0.0/16 | IPv4 | 65,536 |
Look up an address on AS6871
The field is prefilled with 31.108.0.1, the first address of the largest range above. Change it for one from your own logs and you get the network, the operator and the verdict for that specific address.
What AS6871 means for detection
Addresses on British Telecommunications PLC are consumer connections: households and small businesses on a fixed line. Our engine classifies them residential, which is the class most likely to be a real customer, and the class fraud tools are least likely to flag. The catch is the residential proxy. An address here can be rented out by whoever holds the connection, and when that happens the ownership data on this page still reads as clean. That is a behavioural signal, not an ownership one.
The verdict for a single address is never settled by the ASN alone. It is the starting point, and IP Detection adds range membership, behaviour and history on top of it before it answers.
Related networks
The same page as JSON
No key and no signup. This is the endpoint this page is rendered from, so anything you read here you can script against.
curl https://ipscanner.io/v1/asn/directory/AS6871
IPScanner. AS6871 British Telecommunications PLC, ASN directory. https://ipscanner.io/fr/asn/as6871. Derived from MaxMind GeoLite2.