Overview
ssh passwordless login is done using a public/private key pair. The private key is is kept on the system you want to login from; the public key is copied to the system and user you want to login to.
Setup procedure
- Generate a public/private key pair following the procedure on ssh key generation
- Copy the public key to the system and user you want to login to, adding it to the user's ~/.ssh/authorized_keys file. If the file does not exist, create it and set the permissions to read and write for the user only (
rw-------
).
Usage
ssh <username>@<host>
If username is not specified, it defaults to the current user name
Examples:
ssh root@backupserver
ssh backupserver
ssh bl@192.168.28.2
In case you prefer a password protected key or you want to "hop" from system to system, SSH Agent Forwarding is helpful.