https://www.certdepot.net/rhel7-get-started-firewalld/ https://www.linuxjournal.com/content/understanding-firewalld-multi-zone-configurations https://computingforgeeks.com/install-and-use-firewalld-on-ubuntu-18-04-ubuntu-16-04/

1sudo firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.10.9" service name="ssh" accept' --permanent 2sudo firewall-cmd --remove-service ssh --permanent ## needed, otherwise ssh will still be allowed for all 3sudo systemctl reload firewalld See details in …