How to Authenticate Users to a SSH Server ubuntu on VPS

Download link:
        Putty          : ftp://ftp.chiark.greenend.org.uk/users/sgtatham/putty-latest/x86/putty.exe
        Puttygen    : http://the.earth.li/~sgtatham/putty/0.64/x86/puttygen.exe
       
Commands :

#sudo -s
"root password"

# cd /home/allitseasy

# sudo ssh-keygen -t rsa 

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa):  

/root/allitseasy/id_rsa  

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa): /root/allitseasy/id_rsa 

Enter passphrase (empty for no passphrase): Pa$$w0rd

Enter same passphrase again: Pa$$w0rd 

# ls -la /home/allitseasy/

-rw------- 1 root       root       1766 Apr 27 19:36 id_rsa
-rw-r--r-- 1 root       root        397 Apr 27 19:36 id_rsa.pub

#sudo cat  /home/allitseasy/id_rsa.pub >> /root/.ssh/authorized_keys 

#sudo service ssh restart

#sudo nano /etc/ssh/sshd_config

change

PasswordAuthentication  no

with

PasswordAuthentication  yes

 #sudo service ssh restart