Firewall

Is it already on?

openSUSE normally comes with firewalld enabled. It manages the firewall rules that control network connections to your computer.

The default settings are a sensible starting point for everyday use. Browsing and downloads work normally, while incoming connections are limited to allowed services.

Check if it’s running

Open a terminal and run:

sudo firewall-cmd --state

If it says running, firewalld is on.

What settings is it using?

Firewalld groups its rules into zones. A zone is simply a set of firewall settings for a network connection.

To see which zone your connection uses, run:

sudo firewall-cmd --get-active-zones

You’ll normally see public. This limits connections from other devices to the services you’ve allowed.

To see the rules for that zone, run:

sudo firewall-cmd --zone=public --list-all

Do I need to change anything?

You can leave the default settings as they are for everyday use.

File sharing, finding network printers, or hosting a game may need an extra rule. Follow the app’s instructions and allow only what it needs.