Thanks for your Reply, and sorry for my late reply.
- do you only need data integrity or also data confidentiality?
Data confidentiality since it will be read only just for User-Auth.
- which kind of data is stored inside the LDAP server?
Employee data like names, E-Mail, password
- how do LDAP clients access the server?
We want to connect our public git with our local UCS-Server (just for Auth)
- which OS is the LDAP server running on?
Debian 9
- against which attacks do you want to protect your deployment?
We only want to do Gittea user Auth against UCS/LDAP, therefore Proxy/Filter came into our mind to filter out only the needed requests. E.g. in order to Auth a User you don't need to query its telephone number.