What is a well-known service that binds port 25 and is it required on all hosts?

You’ve been reviewing your security checklist and one of the items calls for reviewing the /etc/passwd file. You cat the file and notice that, while most users have an x in the second column, a few have a 14 character string in the second column.

What action, if any, should you take?

You want to change the aging information in the /etc/shadow file. What is the best utility to use to do this?

The files /etc/hosts.allow, /etc/hosts.deny and /etc/nologin all exist on your computer and the sshd daemon is running. What will happen when users try to connect with ssh?

The legacy program for listing files in the printer queues from the command line is:

To prevent a specific user from scheduling tasks with at, what should the administrator do?

What should the permission settings be for /etc/passwd and /etc/shadow?

Which of the following configuration files should be modified to set default shell variables for all users?

What command prints available functions?

Your FTP server has been under attack, and the ISP of the attacker has been less than helpful in mitigating the attacks. So you decide that all connections from that ISP (badguy.example.org) to your FTP server will be denied and sent a message. Which line in your /etc/hosts.allow will have the desired effect?