AS5432: the PROXIMUS-ISP-AS network

AS5432 is an internet Autonomous System operated by PROXIMUS-ISP-AS (Belgium). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS5432?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS5432 was assigned to PROXIMUS-ISP-AS by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS5432 currently announces 38 IPv4 block(s), totaling about 3.9 million addresses (3,917,056 in all), registered in Belgium. Services from PROXIMUS-ISP-AS are reached through these addresses.

What it means to see AS5432 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS5432. That means the other end sits on the PROXIMUS-ISP-AS network (Belgium). 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.