No password SSH – Login to a SSH server with private/public keys

If you often need to establish SSH connections to a server, entering the password each time may be an hassle or even a non-starter. For example, in our case we use ssh connections in our nightly build scripts, so obviously entering a password would not be an option here…

So it can be useful to configure the server and you client to accept secure ssh connection without the need to enter a password.  What must be done, then , is to generate a public/private key pair, and copy the public part into the appropriate place on the server side.

For doing this, on the user’s home directory, on the client machine, type:

-t tells the type of encryption
-f tells where to store the public/private key pairs. In this case, the .ssh directory on home is being used

A password will be asked;  leave this part blank, just press <enter>
Now, go the .ssh directory, and you will find two new files: id_dsa and The last one is the public part. Now, copy the public key to the server machine:

Of course, this time you will need to enter the password. Now, login into the server machine and go to the .ssh directory on the server side

Then add the client’s public key to the known public keys on the server:

and that’s all. Next time you log into the remote server, no password will be asked. If that does not work, you can try to use authorized_keys instead of authorized_keys2, since it may depends on the Linux version used.

Note that this system will work while none of the machines change its IP address and for the specific user, so it is still safe.

Reference: (Link is down now)

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[…] to install GNU parallel on all computers and setup your machines so that they can be accessed by ssh without password. (using public/private keys instead).The task is the same, but the command line becomes a little […]


[…] to login via SSH with a key, and I can’t add an extra key by myself, as described in “No Password SSH” post. The private key (RSA) has been generated with ssh-keygen in Linux, and I can login […]

Chris Steinbach
Chris Steinbach
2 years ago

The last steps can be replaced with an invocation of the ssh-copy-id command (see