firewall-cmd --add-service=pop3s --permanent firewall-cmd --add-service=imap4s --permanent firewall-cmd --add-service=imaps --permanent firewall-cmd --reload firewall-cmd --add-service=dns --permanent firewall-cmd --reload systemctl start firewalld firewall-cmd --get-active-zones firewall-cmd --list-all --zone=public firewall-cmd --remove-service=dhcpv6-client --zone=public --permanent firewall-cmd --reload