AS12701: the BARCAP London network

AS12701 is an internet Autonomous System operated by BARCAP London (the United Kingdom). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS12701?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS12701 was assigned to BARCAP London by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS12701 currently announces 18 IPv4 block(s), totaling about 53 thousand addresses (52,992 in all), registered in the United Kingdom. Services from BARCAP London are reached through these addresses.

What it means to see AS12701 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS12701. That means the other end sits on the BARCAP London network (the United Kingdom). It can be legitimate — a cloud service, an ISP, a CDN — or an unexpected connection worth checking.

How to see every connection and network your devices reach

Tracing one connection's ASN at a time is tedious. Sentinela, by PC Monitor, maps the devices on your network, shows what is exposed to the internet and helps flag suspicious connections and devices — running on your Windows. Meet Sentinela.