Network · AS21273

AS21273 Swisscom (Schweiz) AG

AS21273 (Swisscom (Schweiz) AG) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Network check ASN

AS21273

OwnerSwisscom (Schweiz) AG
KindInternet service provider
Servers, not peopleno
IPv4 addresses768
IPv4 ranges3
IPv6 ranges2

Risk score0

Nothing suspicious found.

Largest IPv4 ranges

212.243.54.0/24
194.209.118.0/24
193.5.252.0/24

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

Check an IP address →

Detect it in code

Spot AS21273 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 AS21273

Is AS21273 a datacenter or VPN network?

AS21273 (Swisscom (Schweiz) AG) looks like an internet service provider, so its addresses are mostly real home, business or mobile connections.

Who owns AS21273?

AS21273 is registered to Swisscom (Schweiz) AG. It announces about 768 IPv4 addresses.

How do I detect traffic from AS21273?

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.