How Websites Detect and Block VPN Traffic

Websites can't see inside your VPN tunnel, but they can often tell you're using one. Streaming services, banks and shops use that to block or challenge VPN users. Here's how detection works.

How sites detect VPNs

• IP address databases. Companies such as MaxMind and IPinfo sell lists of IP addresses that belong to VPN providers, data centers and proxies. Most VPN servers sit in data centers, which is easy to flag.
• Many users on one address. Hundreds of accounts logging in from the same IP address is a strong sign of a shared VPN server.
• Leaks. WebRTC, DNS or IPv6 leaks can reveal your real location, which then doesn't match the VPN's.
• Mismatched signals. Your browser's time zone and language don't match the country of your IP address.
• Traffic patterns. Network operators, including some governments, can recognize VPN protocols in the traffic itself.

Why sites block VPNs

• Licensing: streaming services may only have rights to show content in certain countries.
• Fraud prevention: banks and shops see more fraud from anonymous addresses, so they add checks or block them.
• Abuse: sites limit spam, scraping and fake accounts from shared addresses.
• Legal rules: some services must restrict access by country.

Legitimate options

• Split tunneling: let your bank or a local streaming app connect directly while the rest of your traffic uses the VPN. See split tunneling explained.
• A dedicated IP address: many VPNs sell an address only you use, which looks less suspicious to banks.
• A nearby server in your own country, for sites that only block foreign access.
• Fix leaks: WebRTC Privacy Shield stops Chrome revealing your real IP address through WebRTC, which keeps your location consistent.

Using a VPN to get around a service's terms can get your account suspended, so check the rules for services you pay for.

VPNs that block harmful sites

Many VPNs include an optional filter that blocks known malware, phishing and tracking domains, such as Proton VPN's NetShield or NordVPN's Threat Protection. These work like a DNS filter. They help, but don't replace Chrome's own Safe Browsing protection, which you should keep turned on.

Test your setup

Run leak tests while connected, to see what sites see. See free VPN leak tests and how to prevent IP leaks in Chrome.