You can create a firewall from the Firewall section or from the settings of a particular service.
To create a firewall:
Go to Networks → Firewall and click Create.
Choose what this firewall needs to do: allow traffic or deny traffic.
Set firewall rules for incoming and/or outgoing traffic. Later on, you will be able to edit the rules, delete them or add new rules.
Select which services the rules should apply to. This setting can also be changed later on.
Provide your firewall name if necessary and click Create.
You can also create a firewall from the service's Network tab: scroll to the Firewall block and click Configure. A page for creating a new group of rules will open, where you can set rules, add services and save a new firewall.
For DBaaS:
For load balancers:
For cloud servers: