Sujit Kumar Shah

Generally you are used $_SERVER['REMOTE_ADDR'] to find out the client's IP address in PHP. But it may not return the true IP address of the client at all time. If your client is connect to the Internet through Proxy Server then $_SERVER['REMOTE_ADDR'] in PHP just returns the IP address of the Proxy Server not of the client's machine. So here is a simple function in PHP to find out the real IP address of the client's machine. There are extra Server variable which might be available to determine the exact IP address of the client's machine in PHP, they are HTTP_CLIENT_IP and HTTP_X_FORWARDED_FOR.

The CAPTCHA  is a very very useful test to prevent abuse on the websites. When you create a web form like registration, login, contact us, blog comment etc..., We are suffering day by day with unwanted email or web spam abuse. So if you use CAPTCHA on your website forms, this can help in stopping Guestbook Spam, Blog Spam, Wiki Spam, Comment Spam, Feedback Form Spam, Other Types of Web Form Spam.

The goal of this tutorial is to demonstrate how to make your own simple CAPTCHA protection using PHP. For this we needed to enabled gd library, you can create a captcha code for your registration form or any web forms using PHP.