How to login without password using putty- Private key / Public authentication – ssh

How to login without password using putty- Private key / Public authentication – ssh

This is how I setup a password less authentication using putty to one of the unix/linux box.
I am assuming that you are trying to login from a windows box using the ssh tool ‘putty’ to a Unix/Linux box.

Prerequisites

Putty
Puttygen

On your windows system

1.  Open putty-gen create a public key and private key, it is very much self explanatory how to
create a public key and private key once you open the tool putty-gen.
2.  Go to unix system and complete step 1 to 7
3.  Login to unix using putty as follows
putty  -i [privatekey.ppk] username@hostname

On Unix/Linux system
1.  Login to your unix box
2.  Go to your home dir
3.  Create or locate .ssh folder
4.  Change to .ssh folder (cd ~/.ssh)

5.  Create or append the public key created on windows using puttygen to
the file   called   ‘authorized_keys’
6.  Change the permissions to the file to 700 (chom 700 authorized_keys )
7.  Change the permission of .ssh directory also to 700

workarounds
Authorized_keys needs to be named authorized_keys2 for older versions of sshd

Tags: faq, howto, Linux, quick guide, tips