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Filter origin audit log

When investigating packet drop events, you can use the field Filter Run-Time ID from Windows Filtering Platform (WFP) audits 5157 or 5152.

Event properties.

The filter ID uniquely identifies the filter that caused the packet drop. The filter ID can be searched in the WFP state dump output to trace back to the Firewall rule where the filter originated from. However, the filter ID isn't a reliable source for tracing back to the filter or the rule, as the filter ID can change for many reasons despite the rule not changing at all. The change in ID makes the diagnosis process error-prone and difficult.

To debug packet drop events correctly and efficiently, you need more context about the blocking filter, such as its origin. The blocking filters can be categorized under these filter origins:

  1. Firewall rules
  2. Firewall default block filters
    1. AppContainer loopback
    2. Boot time default
    3. Quarantine default
    4. Query user default
    5. Stealth
    6. Universal Windows Platform (UWP) default
    7. Windows Service Hardening (WSH) default

The next section describes the improvements made to audits 5157 and 5152 in Windows 11 and Windows Server 2022, and how the filter origins are used in these events.

Improved firewall audit

Starting in Windows 11 and Windows Server 2022, two new fields added to the audit 5157 and 5152 events are Filter Origin and Interface Index:

  • The Filter Origin field helps identify the cause of the drop. Packet drops from firewall are explicitly dropped by default block filters created by the Windows Firewall service or a firewall rule that may be created by users, policies, services, apps, etc. Filter Origin` specifies either the rule ID (a unique identifier of a Firewall rule) or the name of one of the default block filters
  • The Interface Index field specifies the network interface in which the packet was dropped. This field helps to identify which interface was quarantined, if the Filter Origin is a Quarantine Default

To enable a specific audit event, run the corresponding command in an administrator command prompt:

Audit # Enable command Link
5157 Auditpol /set /category:"System" /SubCategory:"Filtering Platform Connection" /success:enable /failure:enable 5157(F): The Windows Filtering Platform has blocked a connection.
5152 Auditpol /set /category:"System" /SubCategory:"Filtering Platform Packet Drop" /success:enable /failure:enable 5152(F): The Windows Filtering Platform blocked a packet.

Example flow of debugging packet drops with filter origin

As the audit surfaces Filter Origin and Interface Index, the network admin can determine the root cause of the network packet drop, and the interface it happened on.

Event audit.

The next sections are divided by Filter Origin type, the value is either a rule name or the name of one of the default block filters. If the filter origin is one of the default block filters, skip to the section, Firewall default block filters.

Firewall rules

Run the following PowerShell command to generate the rule information using Filter Origin.

Get-NetFirewallRule -Name "<Filter Origin>"
Get-NetFirewallRule -Name " {A549B7CF-0542-4B67-93F9-EEBCDD584377} "

Firewall rule.

After identifying the rule that caused the drop, the network admin can modify or disable the rule to allow the traffic they want through one of the available tools. The network admin can find the rule in the UI with the rule's DisplayName.

Note

Firewall rules from Mobile Device Management (MDM) store cannot be searched using the Windows Firewall UI. Additionally, the above method doesn't work when the Filter Origin is one of the default block filters, as they don't correspond to any firewall rules.

Firewall default block filters

AppContainer loopback

Network drop events from the AppContainer loopback block filter origin occur when localhost loopback isn't enabled properly for the Universal Windows Platform (UWP) app:

  • To enable localhost loopback in a local debugging environment, see Communicating with localhost
  • To enable localhost loopback for a published app that requires loopback access to communicate with another UWP or packaged Win32 app, see uap4:LoopbackAccessRules

Boot time default

Network drop events from the boot time default block filter origin occur when the computer is booting up and the firewall service isn't yet running. Services need to create a boot time allow filter to allow the traffic. It should be noted that it's not possible to add boot time filters through firewall rules.

Quarantine default

Network drops from the quarantine default block filter occur when the interface is temporarily quarantined by the Firewall service. The firewall service quarantines an interface when it detects a change on the network, and based on several other factors, the firewall service might put the interface in quarantine as a safeguard. When an interface quarantined, the quarantine default block filter blocks any new non-loopback inbound connections.

Run the following PowerShell command to generate more information about the interface:

Get-NetIPInterface -InterfaceIndex <Interface Index>

To learn more about the quarantine feature, see Quarantine behavior.

Note

Quarantine-related packet drops are often transient and signify nothing more than a network change on the interface.

Query user default

Network packet drops from query user default block filters occur when there's no explicit rule created to allow an inbound connection for the packet. When an application binds to a socket but doesn't have a corresponding inbound rule to allow packets on that port, Windows generates a pop-up for the user to allow or deny the app to receive packets on the available network categories. If the user selects to deny the connection in the pop-up, subsequent inbound packets to the app will be dropped. To resolve the drops:

  1. Create an inbound firewall rule to allow the packet for this application. The rule allows the packet to bypass any query user default block filters
  2. Delete any block query user rules that may have been auto generated by the firewall service

To generate a list of all the query user block rules, you can run the following PowerShell command:

Get-NetFirewallRule | Where {$_.Name -like "*Query User*"}

The query user pop-up feature is enabled by default. To disable the query user pop-up, you can run the following command in administrative command prompt:

Netsh set allprofiles inboundusernotification disable

Or in PowerShell:

Set-NetFirewallProfile -NotifyOnListen False

Stealth

Network drops from stealth filters are typically made to prevent port scanning.

To disable stealth-mode, see Disable stealth mode in Windows.

UWP default

Network drops from Universal Windows Platform (UWP) default inbound/outbound block filters are often caused by the UWP app not being configured correctly (that is, the UWP app is missing the correct capability tokens or loopback isn't enabled) or the private range is configured incorrectly.

For more information on how to debug drops caused by UWP default block filters, see Troubleshooting UWP App Connectivity Issues.

WSH default

Network drops from Windows Service Hardening (WSH) default filters indicate that there wasn't an explicit Windows Service Hardening allow rule to allow network traffic for the protected service. The service owner needs to configure allow rules for the service if the block isn't expected.