Which Postfix command can be used to rebuild all of the alias database files with a single invocation and without the need for any command line arguments?

Fill in the blank.
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.)

The content of which local file has to be transmitted to a remote SSH server in order to be able to log into the remote server using SSH keys?

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 command is used to administer IPv6 netfilter rules?