The firewall level lets you control the incoming network traffic and outgoing network traffic between networks.
In Windows, a public network - like in coffee shops - is a type of network wherein anyone has access and through it can connect to other networks.
In Windows, a private network - like your home or your work network - is any connection within a specified network wherein restrictions are established to promote a secured environment.
OS X doesn't differentiate between public and private network.
We do not recommend enabling network services like File & Printer Sharing when connected to public networks as they make your devices more vulnerable to attacks. You should use a VPN connection when connected to public networks.
You can set the level to the following states:
More permissive: File and printer sharing and remote desktop connection are enabled with access to public network.
Secure: By default, file and printer sharing, and remote desktop connection are enabled for private networks. You have the option to enable them for both private networks and public networks.
More secure: File and printer sharing and remote desktop connection are disabled, and access between networks is blocked.
Only outbound and trusted app: All inbound traffic is blocked and only allows access to trusted apps.
For Mac devices, there is no difference in the functionality between the More Secure and Only Outbound & Trusted App levels.
File and Printer Sharing
Lets you safely share files and printers with other devices in the network.
This setting applies only to Windows and OS X devices.
On an OS X device, for file and printer sharing to work, you must first manually enable File Sharing and Printer Sharing on the device. To enable sharing, go to System Preferences >Sharing.
Remote Desktop Connection (Windows only)
Lets you connect to a remote device over a network connection.
Upload Firewall Events
Any blocked firewall events are uploaded from the device to your account.
By default, this setting is disabled to reduce the network bandwidth usage.
This setting applies only to Windows, OS X devices, and Windows servers.
Lets you customize firewall rules for your organization.
Email Protection (Windows Desktops and Laptops only)
Protects your devices against the threats that you might receive through email attachments. It automatically configures your email program for protection against most common email viruses, worms, and other security threats.
You can choose to enable or disable protection to the inbound emails or outbound emails or both.