Ssh password-less access to Haydn

From WikIRI

This is useful ...

... if you have to repetitively login to a remote machine via ssh for instance to access a cvs repository.

This is dangerous...

... after applying this procedure the remote machine is as secure as the local machine.

The procedure

Assuming you want to login from UserLocal in a LOCAL machine to UserRemote in a REMOTE computer (for instance the LOCAL machine can be your desktop computer, the REMOTE one haydn, and the users your local and haydn user names, respectively)

• Check if you have a public-private pair of keys (i.e. the files id_dsa and id_dsa.pub in the .ssh directory in your home folder in the LOCAL machine). If your have them, you can skip next step.

• Generate the public and private ssh-keys in the local machine. When asked for a keyphrase just type enter.

  * ssh-keygen -t dsa

• Copy the public they to the remote machine

  * scp .ssh/id_dsa.pub UserRemote@REMOTE:.

• Login to the remote machine using your password for the last time

  * ssh UserRemote@REMOTE

• Add the public key to the list of authorized servers

  * cat id_dsa.pub >> .ssh/authorized_keys

• If you have problems, is because the .ssh/authorized_keys file doesn't exist. Use instead

  * cat id_dsa.pub > .ssh/authorized_keys

• Remove the public key in the local machine

  * rm id_dsa.pub

• Log out from the remote server

Additional info

• http://www.howtoforge.com/set-up-ssh-with-public-key-authentication-debian-etch
• http://120linux.com/seguridad-en-openssh-adios-a-las-contrasenas/
• http://www.ibm.com/developerworks/library/l-keyc.html

Easy copy id_dsa.pub

# ssh-copy-id -i .ssh/id_dsa.pub test@host