Policy Change Event: 851

Event ID 851 – A change has been made to the Windows Firewall application exception list.

Any change made to the Windows Firewall application exception list triggers event 851. The change in the list can be of any type—it can be the addition, modification, or deletion of an application exception. These changes are generally instituted by an administrator or a group policy refresh.

This log data provides the following information:

• Policy Origin
• Profile Changed
• Change Type
• New Settings - Name
• New Settings - Path
• New Settings - State
• New Settings - Scope
• Old Settings - Name
• Old Settings - Path
• Old Settings - State
• Old Settings - Scope

Why does event ID 851 need to be monitored?

• To monitor the new application exceptions which were created locally
• To monitor the application exception modifications which were carried out locally
• To monitor all deletions of Firewall application exceptions which were done locally

Pro Tip:

ADAudit Plus helps you avoid the GPOs monitoring complexities with real-time pre-configured reports and auditing of the changes along with alerts within a Domain & OU. The advanced Group Policy settings real-time audit reports highlight the elusive change details, and also provide the old and new values of the modified attributes.