When configuring the Windows firewall, many people get confused about what inbound and outbound traffic mean. Let's clarify!
Inbound: This refers to external access. In other words, a computer from outside tries to access your computer (it's external traffic attempting to access the computer).
Outbound: This is traffic originating from your computer that attempts to connect to something externally.
Regarding the firewall, we have:
Inbound Rules
Inbound rules explicitly allow or block traffic attempting to access the computer that matches the criteria in the rule. For example, you can configure a rule to explicitly allow traffic protected by the IPSec protocol to pass to the remote desktop through the firewall, but block it if it's not protected by the protocol.
Outbound Rules
Outbound rules explicitly allow or block traffic originating from the computer that matches the criteria in the rule. For instance, you can set up a rule to explicitly block outbound traffic to a specific computer through the firewall, while allowing the same traffic to other computers. By default, outbound traffic is allowed. Therefore, you need to create an outbound rule to block it.
