Using its standard configuration, how does fail2ban block offending SSH clients?

To allow X connections to be forwarded from or through an SSH server, what configuration keyword must be set to yesin the sshdconfiguration file?

When using mod_authz_core, which of the following strings can be used as an argument to Require in an Apache HTTPD configuration file to specify the authentication provider? (Choose three.)

Which directive in a Nginx server configuration block defines the TCP ports on which the virtual host will be available, and which protocols it will use?
(Specify ONLY the option name without any values.)

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Which directive in a Nginx server configuration block defines the TCP ports on which the virtual host will be available, and which protocols it will use? (Specify ONLY the option name without any values.)