Install & configure SSH in CentOS 6.X

Today I am going to start writing an article about SSH installation and configuration in CentOS. SSH means Secure Shell. When ever we are doing any kind of remote transmission though telnet,It will transmit the information as clear text and anybody is in the network can see whats being transferred and username/password and other sensitive information which supposed to be very secure.So to protect remote data operations SSH invented.
For Information :
--------------------- How to install SSH ----------------------
Open your terminal and type

yum install openssh-server openssh-clients

After installing it , we have to make it as autostart with system boot. to make it so execute below command
chkconfig sshd on
To start,stop,restart and to know status of service

service sshd start
service sshd stop
service sshd restart
service sshd status

Now we have to configure SSH.
Main purpose of SSH is remote host access , so to accept remote incoming connections we must allow the port in IPTables. So add the below line IPTables

vim /etc/sysconfig/iptables
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT

Then restart IPTables

service iptables restart