AS24259: the BC9 kanuma cable television Corporation network

AS24259 is an internet Autonomous System operated by BC9 kanuma cable television Corporation (Japan). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS24259?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS24259 was assigned to BC9 kanuma cable television Corporation by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS24259 currently announces 11 IPv4 block(s), totaling about 21.5 thousand addresses (21,504 in all), registered in Japan. Services from BC9 kanuma cable television Corporation are reached through these addresses.

What it means to see AS24259 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS24259. That means the other end sits on the BC9 kanuma cable television Corporation network (Japan). 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.