# firewall-cmd --permanent --zone=public --add-service=pop3

# firewall-cmd --reload

# firewall-cmd --get-services

# firewall-cmd --info-service=pop3

/usr/lib/firewalld/services/

# firewall-cmd --zone=public --remove-service=pop3

# firewall-cmd --add-port=10000/tcp --zone=public --permanent

# firewall-cmd --remove-port=10000/tcp --zone=public --permanent