Network · AS3661

AS3661 The Chinese University of Hong Kong

AS3661 (The Chinese University of Hong Kong) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Network check ASN

AS3661

  • OwnerThe Chinese University of Hong Kong
  • KindInternet service provider
  • Servers, not peopleno
  • IPv4 addresses73,984
  • IPv4 ranges6
  • IPv6 ranges2
Risk score0

Nothing suspicious found.

Largest IPv4 ranges

  • 137.189.0.0/16
  • 203.188.64.0/20
  • 123.255.64.0/21
  • 175.159.224.0/22
  • 103.49.160.0/22
  • 202.40.216.0/24

Ranges and owner from DB-IP (CC BY 4.0), updated 2026-10-21.

Check an IP address →

Detect it in code

Spot AS3661 traffic at signup.

Send the visitor's IP. The response includes the ASN, the owner and flags.hosting.

curl https://veqen-app.com/v1/ip/check \
  -H "Authorization: Bearer $VEQEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"ip": "203.0.113.7"}'
import os, requests

r = requests.post(
    "https://veqen-app.com/v1/ip/check",
    headers={"Authorization": f"Bearer {os.environ['VEQEN_API_KEY']}"},
    json={"ip": "203.0.113.7"},
    timeout=10,
)
result = r.json()
print(result["risk"]["verdict"], result["risk"]["reasons"])
const res = await fetch("https://veqen-app.com/v1/ip/check", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.VEQEN_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({"ip": "203.0.113.7"}),
});
const result = await res.json();
console.log(result.risk.verdict, result.risk.reasons);
Questions

About AS3661

Is AS3661 a datacenter or VPN network?

AS3661 (The Chinese University of Hong Kong) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Who owns AS3661?

AS3661 is registered to The Chinese University of Hong Kong. It announces about 73,984 IPv4 addresses.

How do I detect traffic from AS3661?

Call the Veqen IP check with the visitor's address. The response includes the ASN, the owner and whether the network is a datacenter, VPN network, relay or ISP.