How can a connection to the server be established using SSH?

To connect to a server via SSH, use the ssh command in the terminal. The format:

ssh [user]@[server_address]

For example, to connect to a server with IP 192.168.1.10 as user 'user':

ssh user@192.168.1.10

If a non-standard port is used, specify it with the -p option:

ssh -p 2222 user@192.168.1.10

After executing the command, you'll be prompted for a password or use a key for authentication, and if successful, you'll enter the remote server's terminal.