Chapter 3 Authentication for FortiOS 5.0 : Single Sign-On to Windows AD : FortiOS FSSO log messages
  
FortiOS FSSO log messages
There are two types of FortiOS log messages — firewall and event. FSSO related log messages are generated from authentication events. These include user logon and log off events, and NTLM authentication events. These log messages are central to network accounting policies, and can also be useful in troubleshooting issues. For more information on firewall logging, see “Enabling security logging”. For more information on logging, see the FortiOS Handbook Log and Reporting chapter.