AS11240: the ATC-BROADBAND network

AS11240 is an internet Autonomous System operated by ATC-BROADBAND (the United States). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS11240?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS11240 was assigned to ATC-BROADBAND by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS11240 currently announces 11 IPv4 block(s), totaling about 13.8 thousand addresses (13,824 in all), registered in the United States. Services from ATC-BROADBAND are reached through these addresses.

What it means to see AS11240 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS11240. That means the other end sits on the ATC-BROADBAND network (the United States). 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.