The Settings tab under Status > System Logs controls how the logging system behaves.
Forward/Reverse Display: Controls whether the logs are displayed in forward or reverse order. Forward order has the newest messages at the bottom of the display. Reverse order has the newest message at the top of the display. This is completely up to the user, letting them choose however they prefer to read the logs. Default is unchecked (forward order).
GUI Log Entries to Display: The number of entries to show in GUI logging tabs. The actual log files hold more entries, so this number may be increased at will. This will not resize the log files, however, only how many are displayed.
Log Firewall Default Blocks: Controls what logging is performed for default rules. The options for block rules are checked by default.
Web Server Log: Controls whether or not the GUI web server process itself will write its messages to the main system log. While useful for troubleshooting, it can be quite chatty and log some harmless but scary-looking messages.
Raw Logs: Selecting this option will display the contents of log files as-is without any parsing from the GUI. Logs such as the firewall log and PPTP VPN log are parsed and displayed in a simpler fashion, making them easy to read and follow in the GUI. To see more detail, check Show raw filter logs and then view the log file again.
Filter descriptions: Controls whether (and how) or not to display the firewall rule descriptions in the log. By default they are not shown, but can be viewed by clicking the action icon ( or ) at the far left of the firewall log entry. Using this option, they may also be displayed in an additional column or a separate row.
Local Logging: Local logging on the firewall may be disabled as well using Disable writing log files to the local disk.
Reset Logs: Pressing this button will clear log data from all of the logs managed by the pfSense base system. All logs are reinitialized having zero entries. The DHCP daemon is restarted when resetting logs.
Log entries may be sent to as many as three remote syslog servers instead of held locally. When using a remote syslog server, there is a choice of which types of events to send.
Be sure that the receiving syslog server is configured to allow logging from this pfSense firewall.
Source Address: Chooses which interface on pfSense to use for initiating log messages. If the target syslog server is across an IPsec tunnel, this should be a local interface address inside of a Phase 2 definition for the IPsec tunnel.
IP Protocol: Selects IPv4 or IPv6 to be used for sending log messages when multiple possibilities exist.
Enable Remote Logging: When checked, send syslog entries to the defined servers.
Remote Syslog Servers: List of remote syslog servers. Can be an IP address (IPv4 or IPv6), hostname, or IP:port if syslog is on a non-default port.
Remote Syslog Contents: Select the items which will be sent via remote syslog. Everything is the preferred choice.