====== Configure Additional Options Described In Documentation ======

**General Information**

Additional SSH options.

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====== Lab Setup ======

The following virtual machines will be used:
  * server1.example.com (192.168.1.150) -> The SSH client
  * server2.example.com (192.168.1.151) -> The SSH server

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====== Initial Setup ======

Install package and generates system keys (should almost always be installed)
<code bash>
yum install openssh-server
</code>
  * openssl is a dependency

\\
Enable and start sshd
<code bash>
systemctl enable sshd
systemctl start sshd
</code>

\\
Allow through firewall
<code bash>
firewall-cmd --permanent --add-service=ssh
firewall-cmd --reload
</code>

====== SSHD Config File ======

  * SSH Daemon config file: /etc/ssh/sshd_config
    * Configure additional options here
    * See man sshd_config

Some useful options
  * Port -> TCP listening port for sshd
  * PermitRootLogin -> Allow/disallow root login
  * MaxAuthTries -> Number of authentication tries. When 1/2 the number is reached, failures are logged.
  * MaxSessions -> Max number of ssh sessions from one IP address
  * AllowUsers -> Space-separated list of users allowed to connect
  * DenyUsers -> Space-separated list of users to deny conections
  * PasswordAuthentication -> Whether to allow password authentication or not.
  * GSSAPIAuthentication -> Authentication through GSSAPI enabled or disabled. Used for kerberos
  * ClientAliveInterval -> Interval in seconds packets are sent to the client to see if the client is still alive.
  * ClientAliveCountMax -> Number of client alive packets to send.
  * UseDNS -> Use DNS name lookup to match an incoming IP address to name. (if on)

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