====== Nginx ======
\\
===== Whitelist certain IP's =====

Add the following directives with your desire IP inside the server section of ///etc/nginx/sites-available//

<code>
server {
    allow 192.168.0.0; # here goes the IP you want to allow
    deny all;
    # ...
}
</code>

You can also write the directives inside the http section to apply it to multiple virtual hosts.
<code>
http {
    allow 192.168.0.0; # here goes the IP you want to allow
    deny all;
    
    server {
        server_name page1.rackspace.com;
        # ...
    }
    
    server {
        server_name page2.rackspace.com;
        # ...
    }
}
</code>
\\
===== Redirect blocked IP's to different URL =====

Use the error_page directive for this.

<code>
location / {
    allow 198.168.0.1;
    deny all;
    error_page 403 http://www.google.com/;
}
</code>