Network · AS2501

AS2501 The University of Tokyo

AS2501 (The University of Tokyo) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Network check ASN

AS2501

OwnerThe University of Tokyo
KindInternet service provider
Servers, not peopleno
IPv4 addresses200,704
IPv4 ranges4
IPv6 ranges1

Risk score0

Nothing suspicious found.

Largest IPv4 ranges

157.82.0.0/16
133.11.0.0/16
130.69.0.0/16
192.51.208.0/20

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

Check an IP address →

Detect it in code

Spot AS2501 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 AS2501

Is AS2501 a datacenter or VPN network?

AS2501 (The University of Tokyo) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Who owns AS2501?

AS2501 is registered to The University of Tokyo. It announces about 200,704 IPv4 addresses.

How do I detect traffic from AS2501?

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.