Chapter 3 Authentication for FortiOS 5.0 : Agent-based FSSO : Configuring the FSSO Collector agent for Windows AD : Configuring Directory Access settings : BaseDN example
  
BaseDN example
An example DN for Training Fortinet, Canada is DN = ou=training, ou=canada, dc=fortinet, dc=com. If you set the BaseDN to ou=canada, dc=fortinet, dc=com then when Fortinet Single Sign On Agent is looking up user credentials, it will only search the Canada organizational unit, instead of all the possible countries in the company. Its a short cut to entering less information and faster searches.
However, you may have problems if you narrow the BaseDN too much when you have international employees from the company visiting different offices. If someone from Fortinet Japan is visiting the Canada office in the example above, their account credentials will not be matched because they are in DN = ou=japan, dc=fortinet, dc=com instead of the BaseDN ou=canada, dc=fortinet, dc=com. The easy solution is to change the BaseDN to simply be dc=fortinet, dc=com. Then any search will check all the users in the company.