Installation guide

102 Chapter 9. OpenSSH

be prompted for both. From this point on, you should not be prompted for a password

by ssh, scp, or sftp.

9.3.4.5. Conﬁguring ssh-agent

The ssh-agent can be used to store your passphrase so that you do not have to enter it

each time you make a ssh or scp connection. If you are not running the X Window System,

follow these steps from a shell prompt. If you are running GNOME but you do not want to

conﬁgure it to prompt you for your passphrase when you log in (see Section 9.3.4.4), this

procedure will work in a terminal window, such as an xterm. If you are running X but not

GNOME, this procedure will work in a terminal window, such as an xterm. However, your

passphrase will only be remembered for that terminal window; it is not a global setting.

1. At a shell prompt, type the following command:

exec /usr/bin/ssh-agent $SHELL

Then type the command:

ssh-add

and enter your passphrase(s). If you have more than one key pair conﬁgured, you will

be prompted for each one.

2. When you log out, your passphrase(s) will be forgotten. You must execute these two

commands each time you log in to a virtual console or open a terminal window.

9.4. Additional Resources

The OpenSSH and OpenSSL projects are in constant development, so the most up-to-date

information for them will be found on their websites. The man pages for OpenSSH and

OpenSSL tools are also good sources of detailed information.

9.4.1. Installed Documentation

• The ssh, scp, sftp, sshd, and ssh-keygen commands — These man pages include infor-

mation on how to use these commands as well as all the parameters that can be used with

them.

9.4.2. Useful Websites

• http://www.openssh.com — The OpenSSH FAQ page, bug reports, mailing lists, project

goals, and a more technical explanation of the security features.

• http://www.openssl.org — The OpenSSL FAQ page, mailing lists, and a description of

the project goal.

• http://www.freessh.org — SSH client software for other platforms.