AS6661: the EPT-LU Entreprise des P. et T. Luxembourg network

AS6661 is an internet Autonomous System operated by EPT-LU Entreprise des P. et T. Luxembourg (Luxembourg). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS6661?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS6661 was assigned to EPT-LU Entreprise des P. et T. Luxembourg by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS6661 currently announces 18 IPv4 block(s), totaling about 219.9 thousand addresses (219,904 in all), registered in Luxembourg. Services from EPT-LU Entreprise des P. et T. Luxembourg are reached through these addresses.

What it means to see AS6661 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS6661. That means the other end sits on the EPT-LU Entreprise des P. et T. Luxembourg network (Luxembourg). 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.