vTiger CRM is prepared to authenticate users from LDAP or Active Directory. But this feature massively hidden, as it seems. The following article describes the configuration in detail.
Sometimes one may want to define a specific OU as default location for newly joined computers in an Active Directory Domain. This can be done very easy: redircmd <OU> redircmd OU=Clientrechner,OU=main-location,DC=my,DC=domain,DC=de