windows-itpro-docs/windows/security/operating-system-security/network-security/windows-firewall/configure-logging.md

title, description, ms.topic, ms.date

title	description	ms.topic	ms.date
Configure Windows Firewall logging	Learn how to configure Windows Firewall to log dropped packets or successful connections with CSP and group policy.	how-to	11/14/2023

Configure Windows Firewall logging

To configure Windows Firewall to log dropped packets or successful connections, you can use:

• Configuration Service Provider (CSP), using an MDM solution like Microsoft Intune
• Group policy (GPO)

[!INCLUDE tab-intro]

:::image type="icon" source="../../../images/icons/intune.svg" border="false"::: Intune/CSP

[!INCLUDE intune-settings-catalog-1]

Category	Setting name	Value

[!INCLUDE intune-settings-catalog-2]

Tip

You can also configure Windows Firewall by using an TBD profile in endpoint security. For more information, see Account protection policy settings for endpoint security in Microsoft Intune.

Alternatively, you can configure devices using a [custom policy][INT-1] with the [DeviceGuard Policy CSP][CSP-1].

Setting
Setting name: Turn On Virtualization Based Security OMA-URI: ./Device/Vendor/MSFT/Policy/Config/DeviceGuard/EnableVirtualizationBasedSecurity Data type: int Value: 1
Setting name: Credential Guard Configuration OMA-URI: ./Device/Vendor/MSFT/Policy/Config/DeviceGuard/LsaCfgFlags Data type: int Value:  Enabled with UEFI lock: 1  Enabled without lock: 2

:::image type="icon" source="../../../images/icons/group-policy.svg" border="false"::: Group policy

[!INCLUDE gpo-settings-1]

1. Expand the nodes Computer Configuration > Policies > Windows Settings > Security Settings > Windows Firewall with Advanced Security
2. In the details pane, in the Overview section, select Windows Defender Firewall Properties
3. For each network location type (Domain, Private, Public), perform the following steps
   1. Select the tab that corresponds to the network location type
   2. Under Logging, select Customize
   3. The default path for the log is %windir%\system32\logfiles\firewall\pfirewall.log. If you want to change this path, clear the Not configured check box and enter the path to the new location, or select Browse to select a file location

      Important

      The location you specify must have permissions assigned that permit the Windows Firewall service to write to the log file.

4. The default maximum file size for the log is 4,096 kilobytes (KB). If you want to change this size, clear the Not configured check box, and enter the new size in KB, or use the up and down arrows to select a size. The file won't grow beyond this size; when the limit is reached, old log entries are deleted to make room for the newly created ones.
5. No logging occurs until you set one of following two options:
   • To create a log entry when Windows Defender Firewall drops an incoming network packet, change Log dropped packets to Yes
   • To create a log entry when Windows Defender Firewall allows an inbound connection, change Log successful connections to Yes
6. Select OK twice

[!INCLUDE gpo-settings-2]

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Recommendations

Here are some recommendations for configuring Windows Firewall logging:

• Change the logging size to at least 20,480 KB(20 MB) to ensure that the log file doesn't fill up too quickly. The maximum log size is 32,768 KB(32 MB)
• For each profile (Domain, Private, and Public) change the name from %windir%\system32\logfiles\firewall\pfirewall.log to:
  • %windir%\system32\logfiles\firewall\pfirewall_Domain.log
  • %windir%\system32\logfiles\firewall\pfirewall_Private.log
  • %windir%\system32\logfiles\firewall\pfirewall_Public.log
• Log dropped packets to Yes
• Log successful connections to Yes

On a single system, you can use the following commands to configure logging:

netsh advfirewall>set allprofiles logging allowedconnections enable
netsh advfirewall>set allprofiles logging droppedconnections enable

Parsing methods

There are several methods to parse the Windows Firewall log files. For example:

• Enable Windows Event Forwarding (WEF) to a Windows Event Collector (WEC). To learn more, see Use Windows Event Forwarding to help with intrusion detection
• Forward the logs to your SIEM product such as our Azure Sentinel. To learn more, see Windows Firewall connector for Microsoft Sentinel
• Forward the logs to Azure Monitor and use KQL to parse the data. To learn more, see Azure Monitor agent on Windows client devices

Tip

If logs are slow to appear in your SIEM solution, you can decrease the log file size. Just beware that the downsizing results in more resource usage due to the increased log rotation.

Troubleshoot if the log file is not created or modified

Sometimes the Windows Firewall log files aren't created, or the events aren't written to the log files. Some examples when this condition might occur include:

• Missing permissions for the Windows Defender Firewall Service (mpssvc) on the folder or on the log files
• You want to store the log files in a different folder and the permissions are missing, or aren't set automatically
• if firewall logging is configured via policy settings, it can happen that
  • the log folder in the default location %windir%\System32\LogFiles\firewall doesn't exist
  • the log folder in a custom path doesn't exist

In both cases, you must create the folder manually or via script, and add the permissions for mpssvc.

New-Item -ItemType Directory -Path $env:windir\System32\LogFiles\Firewall

Verify if mpssvc has FullControl on the folder and the files. From an elevated PowerShell session, use the following commands, ensuring to use the correct path:

$LogPath = Join-Path -path $env:windir -ChildPath "System32\LogFiles\Firewall"
(Get-ACL -Path $LogPath).Access | Format-Table IdentityReference,FileSystemRights,AccessControlType,IsInherited,InheritanceFlags -AutoSize

The output should show NT SERVICE\mpssvc having FullControl:

IdentityReference      FileSystemRights AccessControlType IsInherited InheritanceFlags
-----------------      ---------------- ----------------- ----------- ----------------
NT AUTHORITY\SYSTEM         FullControl             Allow       False    ObjectInherit
BUILTIN\Administrators      FullControl             Allow       False    ObjectInherit
NT SERVICE\mpssvc           FullControl             Allow       False    ObjectInherit

If not, add FullControl permissions for mpssvc to the folder, subfolders and files. Make sure to use the correct path.

$LogPath = Join-Path -path $env:windir -ChildPath "System32\LogFiles\Firewall"
$ACL = get-acl -Path $LogPath
$ACL.SetAccessRuleProtection($true, $false)
$RULE = New-Object System.Security.AccessControl.FileSystemAccessRule ("NT SERVICE\mpssvc","FullControl","ContainerInherit,ObjectInherit","None","Allow")
$ACL.AddAccessRule($RULE)

Restart the device to restart the Windows Defender Firewall service.