Interview Questions for Technical Support Engineers

IRAKOZE Yves

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Nov 30, 2020

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1. Explain the role of the Windows Server.
- Windows OS Server acts as a centralized computer that provides specific functions and predetermined
rules for computers, users, and components connected to a network.

2. What is Windows Domain?
- Windows Domain provides access to our user accounts, computers, printers, and security features as part
of database controlled by a domain controller.

3. What is a firewall?
- Firewall is a filter between two or multiple computer sources; it blocks any incoming or outgoing traffic.
Firewalls can be in software or hardware forms.

4. What is TCP/IP?
- TCP is a Transmission Control Protocol that deals with establishing a connection between computers before any data is being sent; in other words, acts as the highway for data packets being sent back and forth used by various Protocols.
For example; HTTP or FTP. TCP also controls and sorts out data packet receive orders.

5. Can you explain the difference between HTTP and HTTPS?
- HTTP stands for HyperText Transfer Protocol used by the majority of websites as means of transmitting website data
and it allows for use of hyperlinks. This Protocol mostly used TCP port 80.
- HTTPS is a securing version of HTTP that allows for identify verification and low level encryption using
TCP port 443.

6. What is DNS and which port does it use?
- DNS stands for “Domain Name System “ and it’s mostly used to interpret Domain names into numeric IP addresses.
DNS uses port 53 TCP or UDP

7. How many queries does DNS perform and which ones?

DNS can perform two types of queries; Iterative and Recursive

8. What is Active Directory?

A service of Window Server OS, Active Directory is used for user and computer authentication within a Domain.
It can also enforce security policies with the use of GPOs which can also be used to push software installs across domain

9. Active Directory database is located where?
Database is under the file name NTDS.DIT; and it is located in the %SystemRoot%\ntds folder of the server

10. What is a Lingering Object?
if an Object is deleted from Active Directory while Domain Controlled is offline it can create a Lingering object
When object is deleted from Active Directory a Tomb Stone (which is temporary) is created which then has to be replicated
by Domain Controller before it expires.

11. What is RAID?
Stand for Redundant Array of Independent Disk and is used to provide data redundancy (mirroring) across multiple hard disks. it can also be utilized to improve read/write performance across the server by using stripping configuration.
For example:
RAID 1: two or more disks with identical data stored (redundancy)
RAID 0:two or more disk, data distributed evenly to improve performance (no redundancy)

12. Which commands would you use in CMD to test network connectivity?
To test network connectivity ping, tracert or ipconfig commands can be used.

13. What does IntelliMirror do?
As part of Windows Server OS, IntelliMirror provides assistance in managing user data, computer information, application, and settings.
This is configured with the user Group Policy that defines business roles, group membership, and locations.
for example, if a user moves to a different computer; the applications; setting, and stores files will follow (“Mirror”)

14. How do we backup Active Directory?
Active Directory can be backed up using NTBACKUP tool that comes with a 2003 server. With the 2008 server a command prompt is used to perform
a backup: type “wbadmin start system state backup — backup target:e”
You can also perform a full server backup through Server Manager (OS 2012+)

15. Do you know what Garbage Collection is?
Garbage Collection is a process designed to free space inside Active Directory.
This is performed by default every 12 hours (defrag).

16. Do you know what is SYSVOL folder is?
System Volume folder is a directory that houses a copy of domain files found on a local hard drive within Domain Controller

This data is shared for purpose of replication across domain: for example user logon scripts and Windows Group Policy

17.Explain What is Group Policy is.
A Group Policy is used to control a user’s desktops, computer configurations, and permissions by creating a template for specific group members.
This makes it easier to control and process large groups of users.
For example; Tech support may have different security permissions compared to regular computer users.

18. Can you name is different types of email servers and ports used?
You can have two types of emails servers:
Incoming Mail Server (POP3 port 110, IMAP 143, HTTP 80)
Outgoing Mail Server (SMTP port 25)

19. What is the difference between forest and a domain?
A Domain is a logic-based group of computers, users, and devices within Active Directory. A Tree is a collection of Domains; in case there are multiple Trees formed a Forest is created.

20. Do you know what Virtual Machine is?
A Virtual Machine is an emulation version of an Operating System. For Example; you can have multiple copies of Windows running on a single computer

21. Do you know what “Tattooing” the registry means?

The Group Policy will make the changes to user’s registry but once the Group Policy is no longer in effect, registry values would not revert back leaving them tattooing

22. What is a proxy or proxy server?
Proxy deals with filtering network traffic in a sense of preventing access to certain websites and can even monitor user web activity.
it can block certain websites from being accessed but it can also act as a measuring of hiding the true origin at the point of access.

23. Can you explain what UDP is?
UDP stands for User Datagram Protocol. Unlike TCP, UDP is constantly broadcasting a connection signal which can allow for faster connection speed-with TCP you have to wait for connection confirmation which takes time.
UDP sends out data without consideration of what is receiving it; sort of like a Radio signal

24. What is the loop-back IP address?
The loopback IP Address is 127.0.0.1 As part of troubleshooting network connection issues; it is used to test Network Interface Card for functionality. If you ping this IP address
and it completes successfully it means your hardware is okay.

25. What is DHCP?
DHCP stands for Dynamic Host Configuration Protocol. The main function of DHCP(server) is to handle the distribution of IP address on a network.
Typically, IP address assigned by DHCP server are “Dynamic”, meaning that they are leased and released dynamically (except static)
To explain it further, if you connect a PC to a network it will get a leased IP address and if you disconnected or move the PC it will be assigned a new IP address

26. What is FTP and Port used?
FTP is a File Transfer Protocol used to transfer large files between computers with a built-in ability to pause the transfer of data. Ports used by FTP are 20 and 21.

27. What is SSH and Port used?
also known as Secure Shell; is used to establish a secure connection between devices which can be anything from computers to switches.
For example; you can use SSH at a cafe and connect to any device anywhere; by establishing a configured Secure Shell tunnel between two devices.
Thus making the connection secure

28. What is the maximum length of UTP cable allowed?
The maximum length of UTP is 90 to 100 meters for a single segment connection. if you have a switch or a repeater it can compensate for this limitation

29. What are the layers of the OSI model and how many?

There are 7 layers of the OSI model: Physical Layer, Data Link, Network, Transport, Session, Presentation, and Application

30. What is the Job of Network Layer?

Network Layer deals with routing, switching, and transmitting of data from one point to another, but this layer is also responsible for error handling and packet sequencing

31. Which Type of network cables are used in networking?
Cat-5 runs at 100Mb/s maximum
Cat-5e can run up to 1Gb/s and
Cat-6 can run up to 10Gb/s
Speeds are rated at 100 meters maximum distance

32. What is a Subnet Mask?
A Subnet Mask holds the information about the network and host address under a subnet.
In order for TCP/IP protocol to figure out this information, it looks at the 32bit subnet mask number
A typical example is 255.255.255.0

33. Can you tell me the difference between a workgroup and a domain?
With workgroup, you have a collection of systems that are connected to the same network but have their own set of rules and permission set local level
With a Domain, you have a group of systems that are bound by the rules of a Domain Controller.

34. Can you please give me an example of a DNS issue?
if a host can not be reached by its name over the network using an IP address indicates a problem with DNS

35. How would you analyze the connection between a local host and a server?
A “Tracert” command is used to accomplish this test. Trace Route can provide detailed path information taken through switches, server, computers in reaching the final destination

36. What is ipconfig command used for?

ipconfig command is used to determine TCP/IP settings, DHCP configuration, DNS, Default Gateway, and Subnet Mask. It can also be used to change Local DHCP settings; for example, ipconfig/release and /renew

37. What is VPN?
A Virtual Private Network allows users to create a secure connection over a public network such as the internet.
This is commonly used by mobile workers in order to access the company’s network from a remote location.

38. What is a Networking Switch?
A Networking Switch is used to create or control a network at the physical layer in which multiple devices are connected and share data. This is accomplished by receiving, processing, and forwarding of data in form of data packets.

39. Explain the OSI (Open Systems Interconnection) model explanation.

The network layer is a layer in the OSI (Open Systems Interconnection) model and the TCP/IP protocol stack. It is responsible for providing logical addressing and routing of data between different networks in a communication system.

The primary function of the network layer is to facilitate communication between devices on different networks. It does this by assigning unique logical addresses, or IP addresses, to each device on the network. The network layer then uses this information to route data packets from the source device to the destination device across the network.

The network layer also provides routing services, which allow data to be transmitted from one network to another. This involves selecting the best path for data transmission based on the destination address and network topology, and then forwarding the data packet to the next router or network gateway along that path.

In addition to addressing and routing, the network layer also provides other important services such as fragmentation and reassembly of large data packets, error detection and correction, and congestion control.

Some common protocols that operate at the network layer include IP (Internet Protocol), ICMP (Internet Control Message Protocol), and routing protocols such as OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol).

Overall, the network layer plays a critical role in enabling communication between devices on different networks and is an essential component of any modern communication system.

The OSI (Open Systems Interconnection) model is a conceptual framework that describes the different layers involved in a network communication system. It consists of seven layers, each with a specific set of functions and responsibilities. These layers are:

Physical Layer: This layer is responsible for the transmission and reception of raw data between devices over the physical network medium. It defines the physical characteristics of the network, such as the type of cable or wireless technology used, and the signaling methods used to transmit data.

Data Link Layer: This layer provides error-free transmission of data over a single physical link. It is responsible for framing, error detection, and flow control. The data link layer is divided into two sub-layers: the Media Access Control (MAC) layer and the Logical Link Control (LLC) layer.

Network Layer: This layer is responsible for the delivery of data between different networks. It provides logical addressing and routing services and ensures that data is delivered to the correct destination on the network. The Internet Protocol (IP) is an example of a network layer protocol.

Transport Layer: This layer provides end-to-end communication services between applications running on different hosts. It is responsible for ensuring that data is delivered reliably and in the correct order. The Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are examples of transport layer protocols.

Session Layer: This layer provides services for managing sessions between applications. It establishes, maintains, and terminates communication sessions between hosts, and provides services such as authentication and encryption.

Presentation Layer: This layer is responsible for the representation of data to the application layer. It provides services for data encryption, compression, and conversion, ensuring that data is presented in a format that the application layer can understand.

Application Layer: This layer provides services to end-users and applications. It is responsible for providing services such as email, file transfer, and web browsing. Examples of application layer protocols include HTTP, FTP, SMTP, and POP.

Overall, the OSI model provides a standardized framework for understanding the different layers involved in network communication, and how they work together to ensure that data is transmitted reliably and efficiently across the network.

40. Explain in brief this networking command Ping, Tracert, Netstat

Ping, Tracert (also known as traceroute), and Netstat are three common command-line tools used for troubleshooting network connectivity issues. Here’s a brief explanation of each, along with a typical example and the key differences between them:

Ping:
Ping is a command-line tool that tests the connectivity between two devices by sending a packet of data to a specific IP address or hostname and waiting for a response. Ping is used to checking if a network connection is available and can help diagnose network problems.

Example: To ping the Google website, you can open a command prompt or terminal and type “ping google.com”. This will send a packet to the Google server and report the response time, indicating the time it takes for the packet to reach the server and return back to your device.

Key Difference: Ping is used to test connectivity to a specific host/device, while Tracert and Netstat are used to provide additional information about the network path and connections.

Tracert:
Tracert (traceroute) is a command-line tool that traces the path that network traffic takes from your device to a specified destination. It provides a list of all the devices that the traffic passes through, showing the IP address and response time for each hop along the way.

Example: To trace the path from your device to the Google website, you can open a command prompt or terminal and type “tracert google.com”. This will display a list of all the routers and servers that the traffic passes through, from your local network to the Google server.

Key Difference: Tracert provides information about the network path and shows where any problems may be occurring along the way.

Netstat:
Netstat (network statistics) is a command-line tool that provides information about network connections and network statistics on your device. It displays a list of all active network connections, including the IP address, port number, and protocol used.

Example: To view all active network connections on your device, you can open a command prompt or terminal and type “netstat”. This will display a list of all active connections, including those established with remote devices.

Key Difference: Netstat provides information about active network connections and can be used to identify potential security issues or network performance problems.

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