While installing hadoop in my local machine , i got following error
ssh -vvv localhost 
OpenSSH_5.5p1, OpenSSL 1.0.0e-fips 6 Sep 2011 
debug1: Reading configura         
        For Linux:
Remove SSH with the following command:
sudo apt-get remove openssh-client openssh-server
Install SSH again with:
sudo apt-get install openssh-client openssh-server
Actually i solved this, I just installed shh daemon.
in terminal :
sudo apt-get install openssh-server
It might be caused by some of the following:
apt-get install ssh openssh-client openssh-serverufw allow sshIf you're certain that you have installed ssh, then it's possible that ssh and/or sshd has been terminated or the server service hasn't been started. To check whether these processes are running use:
//this tells you whether your ssh instance is active/inactive
sudo service ssh status
OR
//this list all running processes whose names contain the string "ssh"
sudo ps -A | grep ssh
It's likely that ssh would be active and running but sshd would not.
To enable them:
sudo service ssh start
NB; - some systems have a restart option but mine didn't
For my case(ubuntu 14.04, fresh installed), I just run the following command and it works!
sudo apt-get install ssh
A way to do is to go to terminal
$ sudo gedit /etc/hosts
***enter your ip address ipaddress of your pc  localhost 
    ipaddress of your pc  localhost(Edit your pc name with localhost) **
and again restart your ssh service using:
$ service ssh restart
Problem will be resolve. Thanks