AS25255: the H3G-AUSTRIA-AS TELE2 AUSTRIA network

AS25255 is an internet Autonomous System operated by H3G-AUSTRIA-AS TELE2 AUSTRIA (Austria). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS25255?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS25255 was assigned to H3G-AUSTRIA-AS TELE2 AUSTRIA by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS25255 currently announces 22 IPv4 block(s), totaling about 575.2 thousand addresses (575,232 in all), registered in Austria. Services from H3G-AUSTRIA-AS TELE2 AUSTRIA are reached through these addresses.

What it means to see AS25255 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS25255. That means the other end sits on the H3G-AUSTRIA-AS TELE2 AUSTRIA network (Austria). 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.