install openssh server

sudo apt-get install openssh-server

check installation

ps aux | grep ssh

ps should output more then 2 lines information.

ps - report a snapshot of the current processes

config

sudo vim /etc/ssh/sshd_config

if you need to disable root login.

change

PermitRootLogin Yes 

to

PermitRootLogin no

if you want to change default listener port 22

# What ports, IPs and protocols we listen for 
Port 22 

restart

sudo /etc/init.d/ssh stop
sudo /etc/init.d/ssh start

Please remember to configure allow hosts and deny hosts in production environment.

resource