The /etc/syslog.conf file is used to configure the syslog daemon, which handles the logging of system messages. The file consists of lines that have the following format:
selector action
The selector specifies the type and priority of the messages to be logged, and the action specifies what to do with the messages. The selector has two parts, separated by a dot: the facility and the priority. The facility indicates the source of the message, such as mail, auth, kern, etc. The priority indicates the severity of the message, such as emerg, alert, crit, err, etc. A priority can also be preceded by an equal sign (=) to match only that priority, or a minus sign (-) to match all priorities except that one.
The action can be one of the following:
A filename, starting with a slash (/), indicating the file to write the messages to.
A hostname, preceded by an at sign (@), indicating the remote host to send the messages to via UDP.
A username, indicating the user to send the messages to via wall.
An asterisk (*), indicating all logged-in users.
A pipe symbol (|), followed by a command, indicating the program to pipe the messages to.
In this question, the correct entry is D. mail.*/var/log/[email protected]. This entry means:
Log all mail related messages (mail.*) to the file /var/log/maillog.
Log all critical mail messages (mail.crit) to the remote host logger.example.org.
The other options are incorrect because:
Option A is missing a dot between mail and crit, and uses the wrong domain name (example.org instead of example.com).
Option B uses an invalid action (syslog://logger.example.org) that is not supported by syslog.conf.
Option C is missing a dot between mail and *.
Option E is missing dots between mail and * and between mail and crit.