AS21351: the CANALPLUSTELECOM network

AS21351 is an internet Autonomous System operated by CANALPLUSTELECOM (GP). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS21351?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS21351 was assigned to CANALPLUSTELECOM by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS21351 currently announces 20 IPv4 block(s), totaling about 202 thousand addresses (201,984 in all), registered in GP. Services from CANALPLUSTELECOM are reached through these addresses.

What it means to see AS21351 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS21351. That means the other end sits on the CANALPLUSTELECOM network (GP). 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.