Network · AS31

AS31 California Institute of Technology

AS31 (California Institute of Technology) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Network check ASN

AS31

OwnerCalifornia Institute of Technology
KindInternet service provider
Servers, not peopleno
IPv4 addresses131,840
IPv4 ranges5
IPv6 ranges1

Risk score0

Nothing suspicious found.

Largest IPv4 ranges

134.4.0.0/16
131.215.0.0/16
192.41.208.0/24
192.31.43.0/24
192.12.19.0/24

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

Check an IP address →

Detect it in code

Spot AS31 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 AS31

Is AS31 a datacenter or VPN network?

AS31 (California Institute of Technology) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Who owns AS31?

AS31 is registered to California Institute of Technology. It announces about 131,840 IPv4 addresses.

How do I detect traffic from AS31?

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.