Here is the block that could be put in .htaccess for wordpress:
Open your .htaccess file from public_html folder and add the following code with your allowed ip.
<Files wp-login.php>
# set up rule order
order deny,allow
# default deny
deny from all
# Allowed IP Ranges
allow from 10.10.4.0/23
allow from 10.30.104./24
# Add additional IPs for access here
errordocument 401 default
errordocument 403 default
errordocument 404 default
</Files>
##Replace the ip addres with your ip address.##
To protect others cms replace wp-login.php with their admin panel access file name.
