Firewalld reject IPs on CentOS 7/8
Use rich-rule $ firewall-cmd --permanent --add-rich-rule="rule family='ipv4' source address='10.0.10.0/24' reject" or add port $ firewall-cmd --permanent --add-rich-rule="rule family='ipv4' source address='10.0.10.0/24' port port='110' protocol='tcp' reject" $firewall-cmd --reload @reject dovecot postfix from external IP and accept internal IP firewall-cmd --permanent --add-rich-rule='rule family=ipv4 port port="25" protocol="tcp" reject' firewall-cmd --permanent --add-rich-rule='rule family=ipv4 port port="110" protocol="tcp" reject' firewall-cmd --permanent --add-rich-rule='rule family=ipv4 port port="143" protocol="tcp" reject' firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address='192.168.0.0/16' accept' firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address='127...