AS37963: the ALIBABA-CN-NET Hangzhou Alibaba Advertising Co.,Ltd. network

AS37963 is an internet Autonomous System operated by ALIBABA-CN-NET Hangzhou Alibaba Advertising Co.,Ltd. (China). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS37963?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS37963 was assigned to ALIBABA-CN-NET Hangzhou Alibaba Advertising Co.,Ltd. by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS37963 currently announces 126 IPv4 block(s), totaling about 9.4 million addresses (9,425,408 in all), registered in China. Services from ALIBABA-CN-NET Hangzhou Alibaba Advertising Co.,Ltd. are reached through these addresses.

What it means to see AS37963 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS37963. That means the other end sits on the ALIBABA-CN-NET Hangzhou Alibaba Advertising Co.,Ltd. network (China). 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.