AS39603: the P4NET P4 Play network operator network

AS39603 is an internet Autonomous System operated by P4NET P4 Play network operator (Poland). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS39603?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS39603 was assigned to P4NET P4 Play network operator by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS39603 currently announces 7 IPv4 block(s), totaling about 565.2 thousand addresses (565,248 in all), registered in Poland. Services from P4NET P4 Play network operator are reached through these addresses.

What it means to see AS39603 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS39603. That means the other end sits on the P4NET P4 Play network operator network (Poland). 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.