CGI Proxy - Common Gateway Interface Proxy

What is CGI?

CGI stands for Common Gateway Interface. It is a standard protocol used by web servers to interface with executable programs (scripts or binaries) to generate dynamic content on web pages.

Why is CGI useful?

  • Enables the generation of dynamic web content.

  • Allows web servers to execute external scripts or applications (e.g., in Python, Perl, C).

  • Facilitates form handling, database interaction, and content customization.

  • Can integrate legacy applications with modern web servers.

How it works?

  • A user requests a web page that uses CGI (e.g., a .cgi or .pl script).

  • The web server receives the request and invokes the CGI program.

  • The program processes input (such as form data) and generates output, usually HTML.

  • The server sends this output back to the user’s browser as the HTTP response.

Where is CGI used?

  • In early dynamic websites and legacy systems.

  • For simple form handling or server-side scripting tasks.

  • In systems where lightweight or custom server scripting is required.

  • Still used in some internal tools or embedded systems.

Which OSI layer does this protocol belong to?

  • CGI operates at the Application Layer (Layer 7) of the OSI model.

  • It is invoked by web servers (like Apache or Nginx) to serve HTTP requests with dynamic content.

IS CGI windows specific?

  • No, CGI is not Windows-specific.

  • It is supported on both Windows and Unix-like systems, including Linux and macOS.

IS CGI Linux Specific?

  • No, CGI is not Linux-specific.

  • Though it is commonly used in Linux web environments, it is cross-platform and works wherever a compatible web server and interpreter are available.

Topics in this section,

  • In this section, you are going to learn

  • Terminology

  • Version Info

  • rfc details

  • setup

  • setup

  • packet details

  • usecases

  • features

  • Reference links