Securing communication to a database server involves ensuring data transmitted over the network is encrypted. Using a VPN establishes a secure tunnel between the client and the server, thereby encrypting all data in transit, making it a priority for secure database communications. While enabling IPv6 might improve network structure and future-proof the system, it doesn't directly secure the data transmitted to the database server. Changing the server's default port can obscure the service from some automated attacks but does nothing to encrypt or otherwise directly protect data in transit. Enabling SSH is not standard for securing communications to database servers as it is more commonly associated with secure shell access to Unix-like systems.