Introduction
VPNs allow users to browse anonymously, but some exploit this to perform fake or malicious submissions. This article outlines methods to detect VPN IPs and secure your website.
1. Use IP Intelligence Services
Integrate services like:
These APIs return flags if the IP is a VPN, proxy, or from a hosting provider.
2. Analyze IP Patterns
Look for behavior such as:
- High submission frequency from the same IP block
- IPs from known data centers or cloud providers
- Sudden changes in geographic regions
3. Enable CAPTCHA
Google reCAPTCHA (v2 or v3) adds human verification. It prevents most automated spam.
4. Monitor User-Agent Headers
VPN-based bots often use unusual or blank User-Agent headers. Log these headers and flag any suspicious patterns.
5. Implement Geo-Fencing & Rate Limits
Limit form submissions to specific countries or IP ranges. Apply rate limits per IP to block abuse.
6. Use Logging and Review Systems
Log every submission with IP, timestamp, and user agent. This helps trace VPN-based activity over time.
7. Combine Multiple Techniques
No single method is foolproof. Combine IP lookup, CAPTCHA, rate limiting, and behavior analysis for best protection.
Conclusion
By proactively detecting VPN IPs, you reduce fake submissions and ensure only legitimate users access your web forms. Implementing these safeguards will help maintain your site's trustworthiness and user experience.