System Administration Fundamentals Flashcards

A user reports they can access a local file server by its IP address (e.g., 192.168.1.10) but not by its hostname (e.g., fileserv.local). Other network services seem to be working correctly. What is the MOST likely cause of this issue?

Answer: The DNS server is unreachable or has an incorrect record for the hostname.

The ability to connect via an IP address confirms that basic network connectivity (cabling, switches, routing via default gateway) between the user and the server is functional. The failure to connect by hostname specifically points to a problem with name resolution, which is the primary function of the Domain Name System (DNS).

A system administrator needs to set the permissions on a critical configuration file, `config.conf`, so that the file's owner can read and write to it, members of the group can only read it, and all other users have no permissions at all. Which of the following `chmod` commands will accomplish this?

Answer: chmod 640 config.conf

The `chmod` command uses octal notation where Read=4, Write=2, and Execute=1. For the owner to have read and write permissions, the value is 4+2=6. For the group to have only read permissions, the value is 4. For others to have no permissions, the value is 0. Combining these gives the command `chmod 640`.

A backup strategy involves performing a full backup on Sunday. On Monday through Saturday, a type of backup is performed that only copies files that have changed since the *last full backup* on Sunday. What is this type of backup called?

Answer: Differential backup

A differential backup copies all data that has changed since the last full backup was performed. In this scenario, each daily backup from Monday to Saturday will contain all changes made since Sunday's full backup. An incremental backup, by contrast, would only copy data changed since the previous day's backup.

A system administrator needs to run a script that cleans up temporary log files on multiple servers every morning at 3:00 AM. Which of the following is the MOST appropriate and standard tool for this scheduled, repetitive task on a Linux system?

Answer: A `cron` job

Cron is a standard time-based job scheduler in Unix-like operating systems. It is specifically designed to automate and execute repetitive tasks (cron jobs) at specified intervals or times, such as 3:00 AM every day, making it the ideal tool for this scenario.

While troubleshooting a performance issue on a Linux server with 4 CPU cores, an administrator observes a 15-minute load average of 8.50. What does this value indicate?

Answer: The system is overloaded, with more processes waiting for CPU time than available cores.

The load average represents the average number of processes in the run queue (running or waiting for CPU time). A load average that is consistently higher than the number of CPU cores indicates the system is overloaded. In this case, a load of 8.50 on a 4-core system means that, on average, there were more than twice as many processes needing CPU resources than the hardware could handle simultaneously.

In a Windows Active Directory environment, what is the primary function of a Group Policy Object (GPO)?

Answer: To enforce security settings, deploy software, and manage user and computer configurations centrally.

Group Policy Objects (GPOs) are a core feature of Active Directory used by administrators to define and control the working environment of users and computers. They can manage a vast range of settings, including password policies, software installations, desktop settings, and security configurations, from a central location.