1. What is the role of a system administrator?

A system administrator is responsible for managing and maintaining the hardware, software, and networks of an organization. They ensure the smooth functioning and security of computer systems.

2. What are the key skills required for a system administrator?

Some key skills required for a system administrator include knowledge of operating systems, network protocols, troubleshooting skills, security management, and good communication skills.

3. What is the difference between a physical server and a virtual server?

A physical server is a tangible piece of hardware that runs an operating system, whereas a virtual server is a software-based emulation of a physical server that runs on a virtualization platform.

4. How would you secure a server?

To secure a server, you can implement measures like regularly patching vulnerabilities, using a firewall, implementing strong user access controls, regularly backing up data, and encrypting sensitive information.

5. What is RAID and how does it work?

RAID (Redundant Array of Independent Disks) is a technology that combines multiple physical drives into one logical unit to improve data redundancy and performance. It can be configured in different levels like RAID 0, RAID 1, RAID 5, etc.

6. Explain the role of Active Directory in Windows Server administration.

Active Directory is a directory service that provides a centralized and hierarchical structure for managing user accounts, groups, and network resources in a Windows Server environment. It simplifies administration tasks and allows for easy access control.

7. What is the purpose of DNS?

DNS (Domain Name System) is used to translate domain names to IP addresses. It acts as a service that maps human-readable domain names to their corresponding IP addresses, facilitating internet communication.

8. How would you troubleshoot a network connectivity issue?

To troubleshoot a network connectivity issue, you can start by checking physical connections, verifying IP configurations, testing with different devices, using network diagnostic tools, and analyzing network logs.

9. What is a backup and why is it important?

A backup is a copy of data stored separately from the original data source, used to restore data in case of data loss or system failure. Regular backups are important to prevent data loss, ensure business continuity, and protect against security incidents.

10. How do you handle a system security breach?

In the event of a security breach, immediate action is essential. This includes isolating affected systems, disabling compromised accounts, notifying relevant authorities, conducting a thorough investigation, and implementing remedial measures to prevent future incidents.

11. How would you monitor the performance of a server?

You can monitor server performance by using tools like resource monitoring utilities, performance counters, log analysis, network monitoring tools, and server health checks. This helps identify performance bottlenecks and ensures optimal system operation.

12. Explain the concept of IP addressing.

IP addressing is a method used to assign unique identifiers to devices (computers, servers, etc.) in a network. It allows devices to communicate with each other over an IP-based network, using either IPv4 or IPv6 protocols.

13. What is the difference between TCP and UDP?

TCP (Transmission Control Protocol) is a reliable and connection-oriented transport protocol that ensures data integrity and ordered transmission. UDP (User Datagram Protocol) is a simpler and connectionless protocol that provides faster but less reliable transmission.

14. How would you handle a user complaint about slow system performance?

To handle a complaint about slow system performance, you can start by investigating the issue, checking resource utilization, analyzing logs, identifying potential bottlenecks, optimizing system configurations, and considering hardware upgrades if necessary.

15. What is a firewall and how does it work?

A firewall is a network security device that monitors and controls incoming and outgoing network traffic based on predefined security rules. It acts as a barrier between internal and external networks, allowing or blocking traffic based on defined policies.

16. What is the purpose of a proxy server?

A proxy server acts as an intermediary between client devices and the internet. It can cache web content, filter requests, provide security features, and enhance performance by reducing bandwidth usage or improving latency.

17. How can you secure a Linux server?

To secure a Linux server, you can implement measures like updating software regularly, configuring strong authentication mechanisms, using a firewall, disabling unnecessary services, employing file system permissions, and implementing intrusion detection systems.

18. How do you ensure data integrity in a database?

To ensure data integrity in a database, you can enforce data validation rules, define constraints and relationships, implement data encryption, regularly backup data, perform integrity checks, and monitor access controls.

19. What are the best practices for system backup and disaster recovery?

Some best practices for system backup and disaster recovery include regularly backing up critical data, testing backups for successful recovery, storing backups off-site, documenting recovery procedures, implementing redundant systems, and reviewing and updating backup strategies periodically.

20. How would you handle a server hardware failure?

In the event of server hardware failure, you can initiate disaster recovery procedures, replace faulty components, restore data from backups, validate system functionality, and communicate the impact and resolution to relevant stakeholders.

1. What is the difference between a user and a group in Linux?
In Linux, a user is a single account that can log in and interact with the system individually. On the other hand, a group is a collection of multiple users with similar privileges and permissions.

2. How do you set file permissions in Linux?
File permissions in Linux can be set using the chmod command. It allows you to specify permissions for the owner, group, and others, using symbols or octal values.

3. Explain the purpose of the sudo command.
The sudo command allows a user with administrative access to execute commands as a superuser or another user. It provides temporary privileges for executing specific tasks without logging in as the root user.

4. What is the purpose of the crontab command?
The crontab command is used to create, edit, and manage cron jobs in Linux. Cron jobs are automated tasks that run at specific intervals or times.

5. How do you check the status of a service in Linux?
The systemctl command can be used to check the status of a service in Linux. For example, “systemctl status apache2” will display the status of the Apache HTTP Server.

6. Explain the difference between RAID levels 0, 1, 5, and 10.
RAID 0: Striping without redundancy
RAID 1: Mirroring without striping
RAID 5: Striping with distributed parity
RAID 10: Combines mirroring and striping

7. How do you troubleshoot network connectivity issues in Linux?
To troubleshoot network connectivity issues in Linux, you can use tools like ping, traceroute, netstat, ifconfig, and tcpdump to diagnose problems at different network layers.

8. What is the purpose of the SSH protocol?
The SSH (Secure Shell) protocol is used for secure remote login, file transfer, and command execution over an encrypted network. It ensures secure communication between a client and a server.

9. Explain the difference between TCP and UDP.
TCP (Transmission Control Protocol) is a connection-oriented protocol that provides reliable and ordered data delivery, while UDP (User Datagram Protocol) is a connectionless protocol that does not guarantee reliable delivery.

10. How do you add a user to a group in Linux?
The usermod command is used to add a user to an existing group in Linux. For example, “usermod -aG groupname username” adds the user to the specified group.

11. What is the purpose of the df command?
The df command in Linux is used to display information about the usage and available space on file systems. It shows the disk space utilization of mounted filesystems.

12. How do you change the default runlevel in Linux?
The default runlevel in Linux can be changed by modifying the /etc/inittab file or using the systemctl command. For example, “systemctl set-default runlevel5.target” sets the default runlevel to graphical mode.

13. Explain the purpose of the ip command.
The ip command is used to manage and monitor network interfaces in Linux. It provides functionalities like configuring IP addresses, routes, and tunnels.

14. How do you manage software packages in Linux?
Software packages in Linux can be managed using package management tools like apt (for Debian-based systems), yum (for Red Hat-based systems), or pacman (for Arch Linux).

15. What is the purpose of the ulimit command?
The ulimit command is used to set and display resource limits for the current shell session or for specific users. It allows administrators to control and restrict resource usage.

16. Explain the purpose of the chroot command.
The chroot (change root) command in Linux is used to create a new root directory for a specific process or group of processes. It provides an isolated environment with limited access to the rest of the system files.

17. How do you configure a static IP address in Linux?
To configure a static IP address in Linux, the network configuration file (/etc/network/interfaces or /etc/sysconfig/network-scripts/ifcfg-eth0) needs to be edited with the desired IP address, netmask, and gateway information.

18. What is the purpose of the visudo command?
The visudo command is used to edit the sudoers file in a safe and secure manner. It ensures that only one person can edit the file at a time, preventing potential syntax errors or conflicts.

19. Explain the concept of SELinux in Linux.
SELinux (Security-Enhanced Linux) is a Linux kernel security module that provides enhanced access control security policies. It implements mandatory access control and provides an additional layer of system security.

20. How do you create a backup of a file or directory in Linux?
The tar command is commonly used to create backups in Linux. It can create a single compressed archive file containing multiple files and directories. For example, “tar -czvf backup.tar.gz directory/” creates a backup of the specified directory.