Restrict 80/443 to IP of web application firewall

We recently positioned the sites on our cPanel servers behind a web application firewall. We now need to restrict access on 80 and 443 to only the IPs of the WAF. What's the best way to go about this? .htaccess, httpd.conf or iptables? Anything else? Looking for advice on any of these options please? Any help would be greatly appreciated.