AS23881: the UDOMAIN-AS-AP UDomain Web Hosting Company Ltd network

AS23881 is an internet Autonomous System operated by UDOMAIN-AS-AP UDomain Web Hosting Company Ltd (Hong Kong). Here is what that means and why this number may show up when you investigate a connection on your network.

What is AS23881?

An Autonomous System (ASN) is a block of networks under a single control with its own routing policy on the internet. The number AS23881 was assigned to UDOMAIN-AS-AP UDomain Web Hosting Company Ltd by an RIR (regional internet registry). All traffic entering or leaving that network is announced under this number.

Reach on the internet

AS23881 currently announces 19 IPv4 block(s), totaling about 18.2 thousand addresses (18,176 in all), registered in Hong Kong. Services from UDOMAIN-AS-AP UDomain Web Hosting Company Ltd are reached through these addresses.

What it means to see AS23881 on your network

When you investigate where a connection from your computer or phone comes from (or goes to), you may find AS23881. That means the other end sits on the UDOMAIN-AS-AP UDomain Web Hosting Company Ltd network (Hong Kong). 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.