What Is a Proxy Server?
A proxy server sits between your device (the client) and the internet, acting as an intermediary. "Proxy" means "substitute" — it accesses websites on your behalf and returns the results to you.
When you route traffic through a proxy, the destination website sees the proxy server's IP address instead of yours, effectively hiding your real IP address. You can check proxy detection results in the Proxy Information section on Kakunin-san.
Types of Proxy Servers
HTTP Proxy
A proxy that relays only HTTP/HTTPS traffic. It's designed specifically for web browsing and can be easily configured in your browser settings. However, it doesn't support non-HTTP protocols like email or FTP.
SOCKS Proxy
A protocol-agnostic, general-purpose proxy. The latest version, SOCKS5, supports both TCP and UDP and includes authentication. It's more flexible than an HTTP proxy and works with any application.
Transparent Proxy
A proxy that automatically relays traffic on the network without the user's awareness. It's commonly deployed in corporate and school networks for content filtering and caching purposes.
Reverse Proxy
Placed on the server side, a reverse proxy distributes incoming client requests to backend servers. It's used for load balancing, SSL termination, and caching. CloudFront and Nginx are widely used as reverse proxies.
Anonymous Proxy
A proxy specifically designed to hide the user's IP address. It's classified by anonymity level:
- Transparent: Forwards the original IP address via the X-Forwarded-For header
- Anonymous: Proxy usage is detectable, but the original IP address is hidden
- Elite/High Anonymous: Even the use of a proxy is difficult to detect
Proxy vs. VPN: Key Differences
Both proxies and VPNs can hide your IP address, but there are important differences.
Encryption
A VPN encrypts all traffic, while most proxies do not. Even with an HTTPS proxy, the connection between the proxy and your device isn't necessarily encrypted.
Scope
A VPN protects all network traffic from your device, whereas a proxy typically only relays traffic from a specific application (such as your browser).
Speed
Proxies can be faster than VPNs because they don't have encryption overhead. However, free proxies tend to be slow due to congestion.
Trustworthiness
VPN services typically offer no-log policies and third-party audits, but the risk of a free proxy operator intercepting your traffic cannot be ruled out.
For more details, see our VPN explainer.
Common Uses for Proxies
- Bypassing geographic restrictions: Access content through a proxy in another country
- Maintaining anonymity: Hide your IP address while browsing
- Content filtering: Restrict access to inappropriate sites in corporate or school networks
- Caching for speed: Cache frequently accessed content to speed up delivery
- Web scraping: Rotate IP addresses to avoid access restrictions
Precautions When Using Proxies
- Free proxies may intercept or tamper with your traffic
- Proxies often don't prevent DNS leaks
- WebRTC leaks can expose your IP address
- Non-HTTPS traffic is not encrypted
- The proxy operator may be logging your activity
Use Kakunin-san's proxy detection feature to verify that your proxy is working correctly.