How to access a website only from a specified IP using PHP -

I need to access only one site from a specific IP address.

It is possible to

This project is under development and some people used it and said "the site is not good" then

I want to avoid things like that The reason is that I need this solutin.

Try it out:

  if ($ _SERVER ['REMOTE_ADDR' ] == "xxxx") echo "admin"; Else "user" echo;  

It checks and takes action of the user's IP.