AS18403: the FPT-AS-AP FPT Telecom Company network

AS18403 is an internet Autonomous System operated by FPT-AS-AP FPT Telecom Company (Vietnam). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS18403?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS18403 was assigned to FPT-AS-AP FPT Telecom Company by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS18403 currently announces 287 IPv4 block(s), totaling about 1.4 million addresses (1,422,072 in all), registered in Vietnam. Services from FPT-AS-AP FPT Telecom Company are reached through these addresses.

What it means to see AS18403 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS18403. That means the other end sits on the FPT-AS-AP FPT Telecom Company network (Vietnam). 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.