Wordpress admin login easily be filtered by IP Address. This method is especially useful as a measure to tackle Brute-force login attack.
This is achieved by placing a .htaccess in the wp-admin directory with the following…
Order Deny,Allow Allow from IP.IP.IP.IP Allow from IP.IP.IP.0/24 Deny from all
You can also use the CIDR notation to Allow/Deny a range of IP addresses.