How to do SSH without Password

SSH supports authentification with Public/Private keys. If you create a key with no passphrase, ssh can be used as convenient rsh replacement with many advantages.

Creating a key pair

ssh-keygen -t rsa

Do not create a dsa key — these are deprecated!

This will create a folder .ssh containing a private key id_rsa and a public one id_rsa.pub.

Authorizing the key

to authorize a key, put its public part in the file authorized_keys in the .ssh directory.

To authorize the key that you just created:

cd ~/.ssh
cat id_rsa.pub >> authorized_keys
chmod 644 authorized_keys

Important: The directory ~/.ssh must not be a symbolic link, or none of this will work!

Tarpits

• Keep your private key SAFE. (check the file permissions)
• The home and .ssh directory must not be writable by group and other users.