This setting determines the behavior for outbound connections that do not match an outbound firewall rule. The default behavior is to allow connections unless there are firewall rules that block the connection. Important If you set Outbound connections to Block and then deploy the firewall policy by using a GPO, computers that receive the GPO settings cannot receive subsequent Group Policy updates unless you create and deploy an outbound rule that enables Group Policy to work. Predefined rules for Core Networking include outbound rules that enable Group Policy to work. Ensure that these outbound rules are active, and thoroughly test firewall profiles before deploying. Vulnerability: Some people believe that it is prudent to block all outbound connections except those specifically approved by the user or administrator. Microsoft disagrees with this opinion, blocking outbound connections by default will force users to deal with a large number of dialog boxes prompting them to authorize or block applications such as their web browser or instant messaging software. Additionally, blocking outbound traffic has little value because if an attacker has compromised the system they can reconfigure the firewall anyway. Counter Measure: Configure this setting to allow outbound connections. Potential Impact: None, this is the default configuration. Fix: (1) GPO: Computer Configuration\Windows Settings\Security Settings\Windows Firewall with Advanced Security\Windows Firewall with Advanced Security\Windows Firewall Properties\Public Profile\Windows Firewall: Public: Outbound connections (2) REG: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\WindowsFirewall\PublicProfile!DefaultOutboundAction [allow/block] (1) GPO: Computer Configuration\\Windows Settings\\Security Settings\\Windows Firewall with Advanced Security\\Windows Firewall with Advanced Security\\Windows Firewall Properties\\Public Profile\\Windows Firewall: Public: Outbound connections (2) REG: HKEY_LOCAL_MACHINE\\Software\\Policies\\Microsoft\\WindowsFirewall\\PublicProfile!DefaultOutboundAction oval:org.secpod.oval:def:40218 SCAP Repo OVAL Definition 2017-04-25