"I wanna display all tickets from client" has nothing to do with your question of "Can you please explain about LDAP Authentication?"LDAP stands for Lightweight Directory Access Protocol. It
is an application protocol used over an IP network to manage and access
the distributed directory information service. This video gives you a
high level overview of LDAP and some examples of software that utilize LDAP, such as Active Directory.If your users want to see all their tickets they need to log into osT using their username and password, this means that they cannot use the "guest access" feature and need to register for accounts (of have your staff register for them) and confirm their email address.