pfSense provides a wealth of information about the state of the firewall, its services, traffic flowing through the firewall, and log data.
Logs on pfSense contain recent events and messages from daemons. These messages can be stored locally on a limited basis, or forwarded to a central logging server for long-term storage, better reporting, alerting, and so on.
.. toctree:: :maxdepth: 1 system-logs firewall-logs filter-log-format-for-pfsense-2-2 gateway-logs ntp-logs package-logs ppp-logs resolver-logs routing-logs log-settings adjusting-the-size-of-log-files copying-logs-to-a-remote-host-with-syslog working-with-binary-circular-logs-clog troubleshooting-login-on-console-as-root-log-messages troubleshooting-promiscuous-mode-enabled-log-messages
These articles cover various ways to check the status of services or features of the firewall, or the firewall itself. They also cover simple network diagnostic tests.
.. toctree:: :maxdepth: 1 show-states show-source-tracking states-summary packet-filter-information gateway-status using-an-alternate-monitor-ip-address-for-gateway-monitoring carp-status interface-status viewing-active-network-sockets services-status smart-status system-activity arp-table arp-moved-log-messages ndp-table hardware-monitoring-support performing-a-packet-capture ping-host test-port traceroute
These articles cover monitoring traffic on interfaces as well as using additional packages for more detailed monitoring of user throughput/usage.
.. toctree:: :maxdepth: 1 monitoring-graphs monitoring-bandwidth-usage traffic-graph exporting-netflow-with-softflowd