Does Windows Defender have a firewall?

Yes, Windows Defender does have a firewall. Windows Defender Firewall is a built-in feature in the Windows operating system that monitors your network for threats and helps to protect your computer from malicious programs. It works in the background to prevent malware and other malicious software from making unauthorized changes to your system.

Windows Defender Firewall uses two types of rules to decide what to block and what to allow: inbound and outbound rules. Inbound rules are used to control which programs or process can communicate with your PC, while outbound rules are used to control which programs or processes can communicate with other networks. When the firewall detects an incoming connection, it will check if there is an inbound rule that matches the connection, and if so, it will either block it or allow it based on the rule. Similarly, when a program sends data to another network, the firewall will check if there is an outbound rule that matches the data, and if so, it will either allow it or block it based on the rule.

Windows Defender Firewall also provides you with granular control over the levels of protection you want to apply to your computer. For example, you can configure the firewall to block all incoming connections, or you can allow specific applications to communicate with your computer. You can also create custom rules for specific applications, such as web browsers, email clients, and instant messaging programs.

Windows Defender Firewall also includes a number of additional features to help protect your computer. These include Intrusion Detection and Prevention (IDP), which blocks malicious programs from infiltrating your system, Network Address Translation (NAT), which allows your PC to remain anonymous on the Internet, and Network Isolation, which blocks untrusted network traffic. Additionally, Windows Defender Firewall also provides logging capability, which allows you to review any suspicious activity that has occurred on your system.

Overall, Windows Defender Firewall provides a great level of security against malicious programs and threats, while still allowing you to have access to the applications and resources you need. It is one of the core features of the Windows operating system and is a key part of Microsoft’s overall security strategy.