If a product includes downgrade rights, the license terms for that product will indicate which earlier versions of the software may be used.

Explanation
These are the port numbers that must be configured on a host-based firewall for a server that needs to allow SSH, FTP, and LDAP traffic. A port number is a numerical identifier that specifies a communication endpoint for a network protocol or an application. A host-based firewall is a software tool that monitors and controls incoming and outgoing network traffic on a single host based on predefined rules. SSH (Secure Shell) is a protocol that allows secure remote access and file transfer over an encrypted connection. The default port number for SSH is 22. FTP (File Transfer Protocol) is a protocol that allows transferring files between hosts over a network connection. The default port number for FTP is 21. LDAP (Lightweight Directory Access Protocol) is a protocol that allows accessing and managing directory services over a network connection. The default port number for LDAP is 389. References:
https://www.howtogeek.com/190014/virtualization-basics-understanding-techniques-and-fundamentals/
https://www.howtogeek.com/220152/what-is-the-difference-between-127.0.0.1-and-0.0.0.0/
https://www.howtogeek.com/428483/what-is-end-to-end-encryption-and-why-does-it-matter/