Windows Firewall: Public: Logging: Size limit (KB)
This DWORD value specifies the maximum size, in kilobytes, of the Windows Firewall log file for the public network profile.
since 0.9.8.11
Purpose
Show registry keys (1)
HKLM\Software\Policies\Microsoft\WindowsFirewall\PublicProfile\Logging\LogFileSize
This DWORD value specifies the maximum size, in kilobytes, of the Windows Firewall log file for the public network profile. A value of 16384 limits the file to 16,384 KB, equivalent to 16 MB.
This increases the documented default limit of 4,096 KB by a factor of four. When the configured limit is reached, Windows removes older log entries to make room for new entries. The file does not grow beyond the specified size.
Notes
Security
A larger log file can retain more connection and packet information. When firewall logging is enabled, this provides a longer record for troubleshooting and investigating security-relevant network activity.
The value does not change firewall rules or traffic-filtering decisions, and it does not enable logging. Under heavy logging activity, older records can still be overwritten once the file reaches 16,384 KB.
Possible side effects
The log file can consume more storage than it does with the documented default limit of 4,096 KB. Changing this limit has no direct effect on network traffic or firewall enforcement.
Notes
This setting applies only to logging for the public firewall profile. Separate settings determine whether dropped packets or successful connections are written to the log.
Microsoft documentation
Microsoft Learn: Configure Windows Firewall logging
Microsoft Learn: Maximum Log File Size registry specification