firewalld allow ports

Check rules

# firewall-cmd --state

Get default zone

# firewall-cmd --get-default-zone

Add allowed ports

# firewall-cmd --zone=public --add-port=50000-51000/tcp

Add permanent allowed ports

# firewall-cmd --zone=public --permanent --add-port=50000-51000/tcp

Check ports and services

# firewall-cmd --zone=public --permanent --list-services
# firewall-cmd --zone=public --permanent --list-ports

Add custom service

# firewall-cmd --zone=public --permanent --add-service=https
# firewall-cmd --zone=public --permanent --add-service=smtp
# firewall-cmd --zone=public --permanent --add-service=imap

After all changes need apply rules

# firewall-cmd --reload