The best way to complete the request to harden the server is to disable port 389 on the server. Port 389 is the default port used by LDAP (Lightweight Directory Access Protocol), which is a protocol that allows access and modification of directory services over a network. LDAP can be used for authentication, authorization, or information retrieval purposes. However, LDAP does not encrypt its data by default, which can expose sensitive information or credentials to attackers who can intercept or modify the network traffic. Therefore, port 389 should be disabled on a web server that only hosts websites and does not need LDAP functionality.
Alternatively, port 636 can be used instead of port 389 to enable LDAPS (LDAP over SSL/TLS), which encrypts the data using SSL/TLS certificates.