AS9621: the II-OKINAWA Okinawa Telecommunication Network Co.,Inc network

AS9621 is an internet Autonomous System operated by II-OKINAWA Okinawa Telecommunication Network Co.,Inc (Japan). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS9621?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS9621 was assigned to II-OKINAWA Okinawa Telecommunication Network Co.,Inc by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS9621 currently announces 13 IPv4 block(s), totaling about 76.8 thousand addresses (76,800 in all), registered in Japan. Services from II-OKINAWA Okinawa Telecommunication Network Co.,Inc are reached through these addresses.

What it means to see AS9621 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS9621. That means the other end sits on the II-OKINAWA Okinawa Telecommunication Network Co.,Inc network (Japan). 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.