You are able to deny or allow all or selected IP addresses or ranges using the .htaccess file. Edit it with any text editor and add this code deny all IP addresses from viewing a site or folder.
order allow,deny deny from all
You can also deny a range of IPs or one particular IP by adding the allow from directive in. The first example will allow all IPs except for 123.456.6.83.
order allow,deny deny from 123.456.6.83 allow from all
And this will deny all IPs from the 123.456.xxx.xxx range.
order allow,deny deny from 123.456 allow from all
Also, you can deny all IPs and only allow certain ones to access the folder. To allow only 123.456.6.83 to access the site, you can use the deny all along with an allow directive.
order allow,deny deny from all allow from 123.456.6.83
And for a range, you can also use the same method
order allow,deny deny from all allow from 123.456