AS48539: the BIFROST-SYSTEMS network

AS48539 is an internet Autonomous System operated by BIFROST-SYSTEMS (Estonia). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS48539?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS48539 was assigned to BIFROST-SYSTEMS by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS48539 currently announces 31 IPv4 block(s), totaling about 9 thousand addresses (8,960 in all), registered in Estonia. Services from BIFROST-SYSTEMS are reached through these addresses.

What it means to see AS48539 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS48539. That means the other end sits on the BIFROST-SYSTEMS network (Estonia). 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.