Ssh without password

Secure shell (ssh) protocols can be configure to work without protocols. This is particularly helpful for machines that are used often.

Configuring ssh without password from a POSIX-compliant terminal

Step 1: create a public key and copy to remote computer

• Log into a local Linux or MacOSX computer
• Type the following to generate the ssh key:

ssh-keygen -t dsa

• Accept the default key location by pressing Enter.
• Secure permission of your authentication keys by closing permission to your home directory, .ssh directory, and authentication files

chmod go-w $HOME
chmod 700 $HOME/.ssh
chmod go-rwx $HOME/.ssh/*

• Type the following to copy the key to the remote server (this will prompt for a password).

cd ~/.ssh
scp id_dsa.pub remote_username@remote_host:/tmp

• Type the following to add the ssh key to the remote user's authorization keys (this will prompt for a password).

ssh remote_username@remote_host 'cat /tmp/id_dsa.pub >>/home/

Step 2: configure the public key from the local computer on the remote computer

• log in to the remote computer using ssh (this will prompt for a password)

ssh remote_username@remote_host

• copy the public key generated on the local computer, that was copied to /tmp on the remote computer, is now appended to .ssh/authorized_keys.

cat /tmp/id_dsa.pub >>$HOME/.ssh/authorized_keys2

• similar to your local computer, make sure the permission on your remote home folder, .ssh folder, and authentication files are properly set (NOTE: this may already be the case).

chmod go-w $HOME
chmod 700 $HOME/.ssh
chmod go-rwx $HOME/.ssh/*

• Lastly, remove the public key from the temporary folder.

rm /tmp/id_dsa.pub