AS31586: the AS-TBNLTN network

AS31586 is an internet Autonomous System operated by AS-TBNLTN (the Netherlands). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS31586?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS31586 was assigned to AS-TBNLTN by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS31586 currently announces 20 IPv4 block(s), totaling about 50.7 thousand addresses (50,688 in all), registered in the Netherlands. Services from AS-TBNLTN are reached through these addresses.

What it means to see AS31586 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS31586. That means the other end sits on the AS-TBNLTN network (the Netherlands). 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.