* Ubuntu SSHD Installation

Type the following two command to install both ssh client and server:
# sudo apt-get install openssh-server openssh-client


To be frank your server is ready by default. Just test it from your home computer or from same system with the command:
# ssh localhost
# ssh user@your-server-ip-address


* How do I use ssh client?

Assuming that your server hostname is userver.mydomain.com and username is vivek, you need to type the following command:
# ssh vivek@userver.mydomain.com

To stop ssh server, enter:
# sudo /etc/init.d/ssh stop

To start sshs server, enter:
# sudo /etc/init.d/ssh start

To restart ssh server, enter:
# sudo /etc/init.d/ssh restart 


Sumber : http://www.cyberciti.biz/faq/ubuntu-linux-openssh-server-installation-and-configuration/