SSH installation on Centos

We need to install two package
                 1. Openssh-server
                 2. Openssh-clients

First check Openssh-server and Openssh-clients packages installed or not

  [root@sysadmin sysadmin]#  rpm  -qa   openssh*
output would like this

openssh-clients-5.3p1-70.el6_2.2.x86_64
openssh-askpass-5.3p1-70.el6_2.2.x86_64
openssh-server-5.3p1-70.el6_2.2.x86_64
openssh-5.3p1-70.el6_2.2.x86_64

You did not get above output .You need to install the Openssh packages ( which are installed by default untill and unless you removed it or skipped it while installing Centos)

           [root@sysadmin sysadmin]#  yum   install  openssh-server   openssh-clients

Then start the SSH service

          [root@sysadmin sysadmin]#   /etc/init.d/sshd   start

After that check SSH service running or not

          [root@sysadmin sysadmin]#   /etc/init.d/sshd   status

If you want to restart the service , using restart command

          [root@sysadmin sysadmin]#   /etc/init.d/sshd   restart

SSH starts automatically whenever the system boot so we will run this command

           [root@sysadmin sysadmin]#   chkconfig   sshd   on