Configuring An Openssh Client; Using The Ssh Command - Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual

Chapter 18. OpenSSH
• ssh_host_rsa_key — The RSA private key used by the sshd daemon for version 2 of the SSH
protocol.
• ssh_host_rsa_key.pub — The RSA public key used by the sshd for version 2 of the SSH
protocol.
User-specific SSH configuration information is stored in the user's home directory within the ~/.ssh/
directory:
• authorized_keys — This file holds a list of authorized public keys for servers. When the client
connects to a server, the server authenticates the client by checking its signed public key stored
within this file.
• id_dsa — Contains the DSA private key of the user.
• id_dsa.pub — The DSA public key of the user.
• id_rsa — The RSA private key used by ssh for version 2 of the SSH protocol.
• id_rsa.pub — The RSA public key used by ssh for version 2 of the SSH protocol
• identity — The RSA private key used by ssh for version 1 of the SSH protocol.
• identity.pub — The RSA public key used by ssh for version 1 of the SSH protocol.
• known_hosts — This file contains DSA host keys of SSH servers accessed by the user. This file is
very important for ensuring that the SSH client is connecting the correct SSH server.
Important
If an SSH server's host key has changed, the client notifies the user that the connection
cannot proceed until the server's host key is deleted from the known_hosts file using
a text editor. Before doing this, however, contact the system administrator of the SSH
server to verify the server is not compromised.
Refer to the ssh_config and sshd_config man pages for information concerning the various
directives available in the SSH configuration files.

18.6. Configuring an OpenSSH Client

To connect to an OpenSSH server from a client machine, you must have the openssh-clients and
openssh packages installed on the client machine.

18.6.1. Using the ssh Command

The ssh command is a secure replacement for the rlogin, rsh, and telnet commands. It allows
you to log in to a remote machine as well as execute commands on a remote machine.
Logging in to a remote machine with ssh is similar to using telnet. To log in to a remote machine
named penguin.example.net, type the following command at a shell prompt:
ssh penguin.example.net
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