Proxy types

HTTP proxy - the most common type of proxy servers.
By the degree of anonymity HTTP proxies can be Transparent, Anonymous and Elite.

Transparent proxy server provide information about the real IP address of the client in the HTTP request headers:

  • REMOTE_ADDR = Proxy's IP.
  • HTTP_VIA = Proxy's IP or name.
  • HTTP_X_FORWARDED_FOR = Client's real IP.

See PHP Script to get visitor's HTTP Request Headers.

Anonymous proxy hides the IP address of the client (no HTTP_X_FORWARDED_FOR header), but indicates that proxy was used during connection.

Elite (High Anonymous) proxy hides the IP address of the client and the fact that proxy was used during connection.

HTTPS proxy - HTTP proxy that supports the CONNECT method (see RFC 2616).
This type of proxy allows to establish a secure connection between the client and server using HTTPS protocol.
It is possible to organize into a chain several HTTPS proxy servers.

SOCKS proxy passes all data from client to server without any change. SOCKS proxies are anonymous.
There are two versions of SOCKS: 4 and 5. SOCKS 5 proxy can require authentication.

Wikipedia: Reverse Proxy is a proxy server that is installed in a server network.
Typically, reverse proxies are used in front of web servers for several reasons:

  • Protecting web server from direct attacks.
  • Caching content for better web server performance.
  • Load balancing: the reverse proxy can distribute the load to several servers.

The best tool to check proxies is Web Proxy Checker.