Create a new file in ~/.ssh called config and insert the following:

Host *
ControlMaster auto
ControlPath ~/.ssh/master-%r@%h:%p


Reuse an existing SSH connection when you connect to the same host multiple times. Be sure to chmod 600 the config file.

Update: This is also nice to add (not supported on all versions of ssh client), ControlPersist 4h

Here’s how to setup SSH so you can use keys for authentication.

1. Create a set of keys:

ssh-keygen -t dsa

2. Hit “Enter” three times, we want the default location for the keys, and no passphrase.
3. You should now have a folder called .ssh in your home folder. Inside are the public and private keys.
4. Use SCP to copy the public key, “id_dsa.pub” to your remote hosts.

scp .ssh/id_dsa.pub me@10.1.2.3:

5. On each host create a .ssh folder in the account you want to access on the remote host (can be multiple accounts).

mkdir .ssh

6. Move (or copy if multiple) the id_dsa.pub file inside the .ssh folder, renaming it to authorized_keys

mv id_dsa.pub ~/.ssh/authorized_keys

7. Set the folder permissions on .ssh to 700.

chmod 700 ~/.ssh


Log out of the host and try logging back in. If everything is still set to defaults, you should be logged into the remote host without using a password.

This method is as secure as the interactive login but you need to guard your private key.