install openssh server
sudo apt-get install openssh-server
ps aux | grep ssh
ps should output more then 2 lines information.
ps - report a snapshot of the current processes
sudo vim /etc/ssh/sshd_config
if you need to disable root login.
if you want to change default listener port 22
# What ports, IPs and protocols we listen for Port 22
sudo /etc/init.d/ssh stop sudo /etc/init.d/ssh start
Please remember to configure allow hosts and deny hosts in production environment.