AS1237: the KREONET-AS-KR KISTI network

AS1237 is an internet Autonomous System operated by KREONET-AS-KR KISTI (South Korea). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS1237?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS1237 was assigned to KREONET-AS-KR KISTI by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS1237 currently announces 121 IPv4 block(s), totaling about 292.4 thousand addresses (292,352 in all), registered in South Korea. Services from KREONET-AS-KR KISTI are reached through these addresses.

What it means to see AS1237 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS1237. That means the other end sits on the KREONET-AS-KR KISTI network (South Korea). 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.