AS43939: the INTERNETIA_ETTH2-AS Noc-Bialystok network

AS43939 is an internet Autonomous System operated by INTERNETIA_ETTH2-AS Noc-Bialystok (Poland). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS43939?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS43939 was assigned to INTERNETIA_ETTH2-AS Noc-Bialystok by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS43939 currently announces 5 IPv4 block(s), totaling about 43 thousand addresses (43,008 in all), registered in Poland. Services from INTERNETIA_ETTH2-AS Noc-Bialystok are reached through these addresses.

What it means to see AS43939 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS43939. That means the other end sits on the INTERNETIA_ETTH2-AS Noc-Bialystok 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.