Network · AS401999

AS401999 Fairfax County NCR

AS401999 (Fairfax County NCR) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Network check ASN

AS401999

OwnerFairfax County NCR
KindInternet service provider
Servers, not peopleno
IPv4 addresses1,024
IPv4 ranges3
IPv6 ranges0

Risk score0

Nothing suspicious found.

Largest IPv4 ranges

76.9.158.0/23
76.9.156.0/24
76.9.155.0/24

Ranges and owner from DB-IP (CC BY 4.0), updated 2026-10-22.

Check an IP address →

Detect it in code

Spot AS401999 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 AS401999

Is AS401999 a datacenter or VPN network?

AS401999 (Fairfax County NCR) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Who owns AS401999?

AS401999 is registered to Fairfax County NCR. It announces about 1,024 IPv4 addresses.

How do I detect traffic from AS401999?

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.