To secure your admin area from hackers, we recommended you to allow access only from your selected IP to your admin directory. You just need to create a .htaccess file in the directory where you want to restrict access by IP Address.

For example, if you have a WordPress blog installed on your main directory like example.com/wp-admin, you should create a .htaccess file in /wp-admin/.htaccess, and you should put this code in, and not forget to replace the allowed IP address with your IP address.

order deny, allow
deny from all
allow from YOUR-IP-ADDRESS-HERE


(Replace "Your-IP-Address-Here" text with your IP Address)

You can test this by accessing your /wp-admin IP address from another IP address which is not allowed by your .htaccess file.