To set up LDAP authentication in Jamf School, you must safelist the necessary IP addresses in your firewall. For more information, see Firewall Ports, IP Addresses, and URLs Used by Jamf School.
It is recommended you use SSL to encrypt the traffic to and from your LDAP server. For more information on enabling LDAP over SSL for Active Directory, see the following article from Microsoft's support website: http://social.technet.microsoft.com/wiki/contents/articles/2980.ldap-over-ssl-ldaps-certificate.aspx For more information on enabling LDAP over SSL for Open Directory, see Open Directory: Enabling SSL for Open Directory with Replicas from Apple's support website.