Network · AS391

AS391 Air Force Systems Networking

AS391 (Air Force Systems Networking) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Network check ASN

AS391

OwnerAir Force Systems Networking
KindInternet service provider
Servers, not peopleno
IPv4 addresses281,856
IPv4 ranges37
IPv6 ranges0

Risk score0

Nothing suspicious found.

Largest IPv4 ranges

137.11.0.0/16
137.0.0.0/16
128.236.0.0/16
128.202.0.0/16
131.15.48.0/21
131.15.160.0/21
131.15.144.0/21
143.141.96.0/22
131.15.68.0/22
131.15.56.0/22
131.15.40.0/22
131.15.236.0/22

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

Check an IP address →

Detect it in code

Spot AS391 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 AS391

Is AS391 a datacenter or VPN network?

AS391 (Air Force Systems Networking) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Who owns AS391?

AS391 is registered to Air Force Systems Networking. It announces about 281,856 IPv4 addresses.

How do I detect traffic from AS391?

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.