AS28660: the OPEN SYSTEM LTDA network

AS28660 is an internet Autonomous System operated by OPEN SYSTEM LTDA (Brazil). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS28660?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS28660 was assigned to OPEN SYSTEM LTDA by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS28660 currently announces 1 IPv4 block(s), totaling about 2 thousand addresses (2,048 in all), registered in Brazil. Services from OPEN SYSTEM LTDA are reached through these addresses.

What it means to see AS28660 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS28660. That means the other end sits on the OPEN SYSTEM LTDA network (Brazil). 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.