Is it possible to turn off user reset / resend password functions?
Becuase we are using LDAP authentication, it will effect the users network access, allowing passwordchanges through IPB board.

You can configure the login method to redirect requests to change one's password to another page.

Great news, thanks, can you point me to the file or section where I can do this?

Tools and Settings >Log In Manager > Edit LDAP Authentication

Find:
Log In User Maintenance URL

There you go.