Network · AS21737

AS21737 SpringNet

AS21737 (SpringNet) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Network check ASN

AS21737

OwnerSpringNet
KindInternet service provider
Servers, not peopleno
IPv4 addresses24,832
IPv4 ranges5
IPv6 ranges1

Risk score0

Nothing suspicious found.

Largest IPv4 ranges

66.119.0.0/19
64.22.224.0/19
76.77.128.0/20
75.98.96.0/20
198.246.200.0/24

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

Check an IP address →

Detect it in code

Spot AS21737 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 AS21737

Is AS21737 a datacenter or VPN network?

AS21737 (SpringNet) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Who owns AS21737?

AS21737 is registered to SpringNet. It announces about 24,832 IPv4 addresses.

How do I detect traffic from AS21737?

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.