Hi,
Do you need LDAP to be reachable from internet ? If not, maybe the best is to firewall the LDAP port and only allow access from localhost and/or your local network only.
The best practice is anyway to only expose on internet the ports that are needed to be reached from outside and FW/close the others.
Sébastien Riccio
System & Network Admin
https://swisscenter.com