WhenIP Academy
How to use WhenIP Header Check
Header Check is helpful when you want to compare direct browsing against VPN, proxy, mobile, or reverse-proxy behavior.
What you'll learn
- Which headers to focus on first.
- How to compare different paths.
- How header clues complement network diagnostics.
Run it in your normal path
Start with a baseline request from the connection you normally use.
Compare after enabling a VPN or proxy
Look for differences in forwarding headers, client hints, and user-agent information.
Focus on meaningful fields
User-Agent, Accept-Language, and any forwarding headers are the most common fields to compare.
Use it with other tools
Combine headers with IP, DNS, and WebRTC checks for a fuller picture of what changed.
Mini FAQ
Why do some headers look generic?
Because browsers reduce entropy and some proxies normalize headers.
Can a proxy add headers I did not send?
Yes. Reverse proxies and security layers often do that.
Last updated: March 29, 2026