To run an OpenSSH server, you must first make sure that you have
the proper RPM packages installed. The openssh-server package is required and depends on
the openssh package.
The OpenSSH daemon uses the configuration file /etc/ssh/sshd_config. The default configuration
file should be sufficient for most purposes. If you want to
configure the daemon in ways not provided by the default sshd_config, read the sshd
man page for a list of the keywords that can be defined in the
configuration file.
To start the OpenSSH service, use the command /sbin/service sshd start. To stop the OpenSSH
server, use the command /sbin/service sshd
stop. If you want the daemon to start automatically at boot
time, refer to Chapter 20 Controlling
Access to Services for information on how to manage
services.
If you reinstall, the reinstalled system creates a new set of
identification keys. Any clients who had connected to the system
with any of the OpenSSH tools before the reinstall will see the
following message:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
|
If you want to keep the host keys generated for the system,
backup the /etc/ssh/ssh_host*key* files
and restore them after the reinstall. This process retains the
system's identity, and when clients try to connect to the system
after the reinstall, they will not receive the warning message.
