Firewalld rich rule example
Allow connection to IP address and specific port only from specified source IP.
firewall-cmd --add-rich-rule='rule family="ipv6" source NOT address="2a01:5f0:c001:106:59:0:2:6" destination address="2a01:5f0:c001:106:59:0:2:30" port port="443" protocol="tcp" reject' --permanent --zone="public"
NOTE: This rule is actually used here in Boldcore for communication between Web server and reverse proxy. So, only reverse proxy can access the web server.
Address 2a01:5f0:c001:106:59:0:2:6 is source address (reverse proxy)
Address 2a01:5f0:c001:106:59:0:2:30 is destination address (web server)