To remotely administer the server, a secure shell program needs installed to accept incoming SSH connections. Install the program with this command:
sudo apt install openssh-server
And then configure the program by editing its settings file with this command:
sudo nano /etc/ssh/sshd_config
And to use the new settings, restart the SSH daemon with this command (or restart the server):
sudo systemctl restart sshd
Then, from another Linux client terminal:
ssh oem@IPADDRESS
From a Windows computer:Download PuTTY