AS9931: the CAT-AP The Communication Authoity of Thailand, CAT network

AS9931 is an internet Autonomous System operated by CAT-AP The Communication Authoity of Thailand, CAT (Thailand). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS9931?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS9931 was assigned to CAT-AP The Communication Authoity of Thailand, CAT by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS9931 currently announces 84 IPv4 block(s), totaling about 278 thousand addresses (278,015 in all), registered in Thailand. Services from CAT-AP The Communication Authoity of Thailand, CAT are reached through these addresses.

What it means to see AS9931 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS9931. That means the other end sits on the CAT-AP The Communication Authoity of Thailand, CAT network (Thailand). 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.