Log dropped packets
This registry value controls logging for network packets dropped by Windows Firewall while the public firewall profile is active.
since 0.9.8.11
Purpose
Show registry keys (1)
HKLM\Software\Policies\Microsoft\WindowsFirewall\PublicProfile\Logging\LogDroppedPackets
This registry value controls logging for network packets dropped by Windows Firewall while the public firewall profile is active. It is a DWORD value: 1 enables dropped-packet logging, while 0 disables it.
The setting does not change firewall rules or determine whether network traffic is allowed or blocked. It records packets that have already been dropped under the effective firewall policy. The public profile applies when Windows classifies a network connection as public.
Notes
Additional effects
Dropped-packet records can help diagnose blocked network communication and identify unexpected connection attempts. These records appear with the action DROP in the firewall log.
This value does not enable logging of successful connections. Successful-connection logging is controlled by a separate setting.
Security
Logging improves the traceability of traffic rejected by the firewall. It does not grant additional network access or weaken firewall filtering.
Firewall logs contain technical information about network traffic. Access to the log file should therefore remain limited to the accounts and services for which it is intended.
Possible side effects
A high volume of dropped traffic causes additional write activity and can make the firewall log reach its configured maximum size more quickly. When that limit is reached, Windows removes older entries to make room for new records, so earlier diagnostic information can be lost.
Notes
The value applies only to the public firewall profile. Equivalent values for the domain and private profiles are stored under their respective profile keys.
Log entries can be written only when Windows Firewall is enabled and the firewall service has write access to the configured log location. The log path and maximum file size are controlled by separate settings.
Microsoft documentation
Microsoft Learn: Configure Windows Firewall logging
Microsoft Learn: Log Dropped Packets registry reference