VPN (Virtual Private Network)

What is a VPN?

A Virtual Private Network (VPN) creates an encrypted tunnel between a user's device and a remote server operated by the VPN provider. All internet traffic passes through this tunnel, so websites and services see the VPN server's IP address instead of the user's real one. This provides two core benefits: privacy, because the user's ISP and local network cannot inspect the traffic, and location masking, because the exit IP can be in a different city or country.

Legitimate vs. Abusive Use

VPNs serve many legitimate purposes. Remote workers use them to access corporate networks securely. Journalists and activists in restrictive regions rely on VPNs to communicate safely. Everyday consumers use them to protect their data on public Wi-Fi networks.

However, bad actors also use VPNs to hide their identity while carrying out credential stuffing attacks, account takeovers, or multi-accounting schemes. Because VPN exit IPs are shared among many users, a single IP address can appear in both legitimate and malicious traffic, making simple IP blocking impractical.

How VPN Traffic Is Detected

Security teams identify VPN connections by maintaining databases of known VPN server IP ranges, analyzing network characteristics such as low latency from a supposedly distant location, and checking for mismatches between the claimed timezone and the IP's geolocation. More advanced approaches combine IP reputation scoring with device fingerprinting to assess risk without relying solely on the IP address.

VPN detection with AntiProxies

AntiProxies ships a downloadable database of VPN, proxy, and Tor exit IP addresses. You load the file into your own infrastructure and run lookups locally — no external calls, no API key, no round-trip latency. When a connection arrives, your code queries the local database and gets back a connection-type classification so you can decide whether to block, challenge with a CAPTCHA, or log the event for review. For a technical deep dive into the methods used, see our blog post on how VPN detection works. For coverage details, see our VPN and proxy detection page.