Questions For IT Interview

Entry-Level and Help Desk Positions

These questions are mostly for Help Desk positions but I wouldn't be surprised if an entry-level candidate was asked any one of these questions. If you don’t know the answer, find it, memorize it and then practice explaining it in your own words.

1. What is the difference between a hub and a switch?

Hub and Switch function exactly the same. They server as a central connection for all your network equipment. Hub broadcast data to all the devices on the network because it does not know the destination. However switch is more intelligent. Switch know exact destination to sent the requested data to. Therefore, switch reduce the network congestion 

2. What is a network?

A network is a group of two or more computer systems linked together. There are many types of computer networks, including:

local-area networks (LANs) : The computers are geographically close together (that is, in the same building). Connected by cable

wide-area networks (WANs) : The computers are farther apart and are connected by telephone lines or radio waves.

campus-area networks (CANs): The computers are within a limited geographic area, such as a campus or military base.

metropolitan-area networks MANs): A data network designed for a town or city.

home-area networks (HANs): A network contained within a user's home that connects a person's digital devices.

In addition to these types, the following characteristics are also used to categorize different types of networks:

topology : The geometric arrangement of a computer system. Common topologies include a bus, star, and ring. See the Network topology diagrams in the Quick Reference section of Webopedia.

protocol : The protocol defines a common set of rules and signals that computers on the network use to communicate. One of the most popular protocols for LANs is called Ethernet. Another popular LAN protocol forPCs is the IBM token-ring network .

architecture : Networks can be broadly classified as using either a peer-to-peer or client/server architecture.

Computers on a network are sometimes called nodes. Computers and devices that allocate resources for a network are called servers.

3. What is Active Directory?
An active directory is a service that is provided by Microsoft that stores information about items on a network so the information can be easily made available to specific users through a log-on process and network administrators. By using an Active Directory it is possible to view an entire series of network objects from a single point and obtain an overall hierarchical view of the network

*It is a service provide by Microsoft. It's like a central database of the organization. It contain all the data about the objects: users, computers, resources like printer and shared folder/file in an organization network . Active Directory is use for authenticate/authorize the user permission based on the stored information. 

Why use active directory: because it is highly secure. it contain policies and permission at different level. 

4. What is TCP/IP and what does it stand for?

Transmission Control Protocol / Internet Protocol. Actually the power of the Internet. TCP make sure the reliability of the packet sent over the network. The IP protocol make sure the packets are sent to the right destination. 

note*: TCP diagram

tcp handshake connection

note*: IP datagram

Hostname: is a name of the device on a network. 

5. What is a default gateway?

Default gateway is basically the gateway which is an IP address that is used as entry point to access the internet. In this case, IP address of the router is the gateway to access the outside network.
*The default gateway is IP address. It is a gateway that connects a local network to the Internet

6. What does DHCP stand for?

Stand for Dynamic Host Configuration Protocol. It is used for assigning the dynamic IP address to the new devices. So we don't have to configure the IP address for every new computers. Internet provider use dynamic IP for subscribers

7. What is an IP Address?

IT is an address (identifier) of a computer or other network device on a network using TCP/IP. Any number from 0 t0 255 could be used for IP address.

8. What is the significance of the IP address 255.255.255.255?

255.255.255.255 is the limited broadcast address (reserved IP address). A broadcast involves delivering a message from one sender to many recipients. It can only be used in LAN. 

9. What are the 3 major classes of an IP network?

The 3 major classes of an IP network are Class A, Class B and Class C. Each class indicates a number of bits per address. For example Class A are the first 8 bits, Class B are the first 16 bits while Class C are the first 24 bits.
 Class A
0 0.0.0.0 126.255.255.255 /8
Class B
10 128.0.0.0 191.255.255.255 /16
Class C
110 192.0.0.0 223.255.255.255 /24

10. What is a Class D IP address?

Class D range 224.0.0.0 to 239.255.255.255. IPv4 networking standard define class D as reserved for multicast. Multicast is used for defining a group and sending IP messages to that group. It does not send to every nodes on the network. Only work within LAN

11. What is OSPF?

stand for "Open Shortest Path First." OSPF is a method of finding the shortest path from one router to another in a local area network (LAN). As long as a network is IP-based, the OSPF algorithm will calculate the most efficient way for data to be transmitted.

12. A user is complaining of delays when using the network. What would you do?
a. ask the user to demonstrate the problem .
b. determined how many are affected by the problem
c. check all the cable and configuration.
d. make sure all the drivers are up to date
e. check for viruses
f. try to restart the computer
g. try to restart the router or switch

Network Administrator Positions

Some of these questions may also be included in the previous category for Help Desk Technician positions. In either case, they’re worth preparing for.

13. What is the difference between layer 2 and layer 3 in the OSI model?

14. What is the difference between a hub, switch, and router? *

15. What is a VLAN?
Virtual LAN. It is a segment on LAN network but without any cable involved. VLAN is configured by software rather than hardware. Therefore, it offer great flexibility. 

16. What is the difference between TCP and UDP?
UDP (User Datagram Protocol) and TCP (Transmission Control Protocol). When transferring data, TPC/IP divides the data into packets which is for faster transmission. When some of the packets are lost during transmission (connection problem), the server will request for the lost packets. On the other hand, UDP/IP does not divide the data into packet and any data checking.

17. How do you distinguish a DNS problem from a network problem?
*The Internet is really based on IP addresses. DNS (Domain Name System) is the service that translates domain names into IP addresses and vice versa.
To determine use NSlookup command in CMD to look up for the ip records. If you are able to ping the ip address but not the domain name, It's a DNS problem. If not able to ping both, IP address and the default gateway, then it's the network problem. 
here is how: http://technet.microsoft.com/en-us/library/aa997324%28v=exchg.65%29.aspx

18. What are a runt, Giant, and collision?

19. What is a broadcast storm?
it is a storm of message that has been broadcast across a network results in even more responses, and each response results in even more responses. The end result is the exhaust of the network resources.

20. What is the purpose of VRRP?
*Virtual router is a backup router used in a VRRP setup
Short for Virtual Router Redundancy Protocol, VRRP is a protocol used to run one ore more routers along with the master VRRP router that helps prevent network downtime. In the event of the master router failing, the backup or virtual router would become the master router.

21. What is a VPN?
Virtual private Network is a private network. It uses encryption and security measure make sure only authorized person can have access to the network. 

22. What is a default route?
*routing table is the map for the routers. Below is the basic routing table.

Network Destination	Netmask	Gateway	Interface	Metric
0.0.0.0	0.0.0.0	192.168.0.1	192.168.0.100	10
127.0.0.0	255.0.0.0	127.0.1.1	127.0.1.1	5
192.168.0.0	255.255.255.0	192.168.0.100	192.168.0.100	10
192.168.5.100	255.255.255.255	127.0.5.1	127.0.5.1	20
192.168.55.255	255.255.255.255	192.168.3.100	192.168.3.100	15

 Default route tell the router or switch where to go if they don't have specific route in their routing table.
23. How do you set a default route on an IOS Cisco router?
https://answers.yahoo.com/question/index?qid=20080625072022AAVPMHr

24. What is a metric?
Metrics is a property of a route in computer networking, consisting of any value used by a routing protocol to determine the fastest route. The lower the number the better. 

25. What is a MAC address?
It is known as physical address. It is a unique ID of the device on the network.Mac address can not be changed

26. What is ARP/RARP?
ARP stands for Address Resolution Protocol. It uses the IP address to map out the Mac address. 
RARP stands for reversed Address Resolution Protocol. It use the Mac address to determine the device's IP address

27. Describe a TCP connection sequence.

is a (very) simplified diagram of the TCP 3-way handshake pro - See more at: http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.pUgaDolj.dpuf

 It referring to TCP 3 ways handshakes: Syn, Syn-ACK, ACK.
Host A send Synchronization packet to Host B
Host B Received Sync packet, and send back Syn-ACK packet back to Host A
Host A received the Sync-ACK and send back ACK packet to B.
Host B receive ACK
and that's how the TCP connection is established

is a (very) simplified diagram of the TCP 3-way handshake pro - See more at: http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.pUgaDolj.dpuf

TCP 3-Way Handshake Diagram

Below is a (very) simplified diagram of the TCP 3-way handshake process. Have a look at the diagram on the right as you examine the list of events on the left.

EVENT	DIAGRAM
Host A sends a TCP SYNchronize packet to Host B Host B receives A's SYN Host B sends a SYNchronize-ACKnowledgement Host A receives B's SYN-ACK Host A sends ACKnowledge Host B receives ACK. TCP socket connection is ESTABLISHED.	TCP Three Way Handshake (SYN,SYN-ACK,ACK)

- See more at: http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.pUgaDolj.dpuf

is a (very) simplified diagram of the TCP 3-way handshake pro - See more at: http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.pUgaDolj.dpuf

is a (very) simplified diagram of the TCP 3-way handshake pro - See more at: http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.pUgaDolj.dpuf

Host A sends a TCP SYNchronize packet to Host B
Host B receives A's SYN
Host B sends a SYNchronize-ACKnowledgement
Host A receives B's SYN-ACK
Host A sends ACKnowledge
Host B receives ACK.
TCP socket connection is ESTABLISHED
- See more at: http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.pUgaDolj.dpuf

TCP 3-Way Handshake Diagram

Below is a (very) simplified diagram of the TCP 3-way handshake process. Have a look at the diagram on the right as you examine the list of events on the left.

EVENT	DIAGRAM
Host A sends a TCP SYNchronize packet to Host B Host B receives A's SYN Host B sends a SYNchronize-ACKnowledgement Host A receives B's SYN-ACK Host A sends ACKnowledge Host B receives ACK. TCP socket connection is ESTABLISHED.	TCP Three Way Handshake (SYN,SYN-ACK,ACK)

- See more at: http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.pUgaDolj.dpuf

TCP 3-Way Handshake Diagram

Below is a (very) simplified diagram of the TCP 3-way handshake process. Have a look at the diagram on the right as you examine the list of events on the left.

EVENT	DIAGRAM
Host A sends a TCP SYNchronize packet to Host B Host B receives A's SYN Host B sends a SYNchronize-ACKnowledgement Host A receives B's SYN-ACK Host A sends ACKnowledge Host B receives ACK. TCP socket connection is ESTABLISHED.	TCP Three Way Handshake (SYN,SYN-ACK,ACK)

- See more at: http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.pUgaDolj.dpuf

28. What is MTU?
 Maximum Transmission Unit, MTU is the maximum size the data packet during the transmission. The default MTU is 1500.

29. What other TCP setting can you modify besides MTU to shorten packets?
Shorten the byte using ping command -l option

System Administration Position

Here are a few more questions that are a little bit more difficult. System Admins should know all these answers by heart in addition to the Network Administrator questions.

30. What is the difference between layer 2 and layer 3 devices?
L-2 devices worked on mac address & L-3 devices worked on ip address. L-2 device faster than the L-3device

31. What is the subnet for a class C network?
For class c Network default Subnet mask is 255.255.255.0 but make sure while putting a question itssubnet or subnet mask

32. Have you configured a NIS server/client before? If so, describe what you did.

33. Have your configured a NFS server?
There are three ways to configure an NFS server under Red Hat Enterprise Linux: using the NFS ServerConfiguration Tool (redhat-config-nfs), manually editing its configuration file (/etc/exports), or usingthe /usr/sbin/exportfs command

34. What are RAID 1 and RAID 5?
Following are the key points to remember for RAID level 1.

•  Minimum 2 disks.
•  Good performance ( no striping. no parity ).
•  Excellent redundancy ( as blocks are mirrored ).

Following are the key points to remember for RAID level 5.

• Minimum 3 disks.
• Good performance ( as blocks are striped ).
• Good redundancy ( distributed parity ).

Best cost effective option providing both performance and redundancy. Use this for DB that is heavily read oriented. Write operations will be slow.

35. What are the required components of Windows Server 2003 for installing Exchange 2003?

36. What must be done to an AD forest before Exchange can be deployed?

37. What Exchange process is responsible for communication with AD?

38. What connector type would you use to connect to the Internet, and what are the two methods of sending mail over that connector?

39. How would you optimize Exchange 2003 memory usage on Windows Server 2003 with more than 1Gb of memory?

40. What are the standard port numbers for SMTP, POP3, IMAP4, RPC, LDAP and Global Catalog?
SMTP-25, POP3-110, IMAP4-143, RPC-135, LDAP-389, GC-3268

41. Name the process names for the following: System Attendant, Information Store, SMTP/POP/IMAP/OWA.

42. What is the maximum amount of databases that can be hosted on Exchange 2003 Enterprise?

43. What are the disadvantages of circular logging?

44. >What is Active Directory schema?

45. What are the domain functional levels in Windows Server 2003?

46. What is the default domain functional level in Windows Server 2003?

47. What are the forest functional levels in Windows Server 2003?

48. What is a global catalog server?

49. How can we raise domain functional and forest functional levels in Windows Server 2003?

50. What is the default protocol used in directory services?

51. What is IPv6?
IPv6 (Internet Protocol version 6) is similar to those of IPv4 -- devices can use IPv6 as source anddestination addresses to pass packets over a network. The most obvious improvement in IPv6 over IPv4 is that IP addresses are lengthened from 32 bits to 128 bits. IPv6 also supports auto-configuration to help correct most of the shortcomings in version 4, and it has integrated security and mobility

52. What are the physical & logical components of ADS?

53. In which domain functional level, we can rename a domain name?

54. What is multimaster replication?

55. What is a site?

56. Which is the command used to remove active directory from a domain controller?

57. What is the file that’s responsible for keeping all Active Directory databases?

General HR Questions

These general questions can be the toughest ones to get through. They might sound easy, but they require a lot of thought and preparation. I would suggest writing down your answers first, then reading them over a few times so that you’re comfortable in answering them.

Some of these questions are very tricky and can get you in trouble. So if you run into problems finding a good answer, check out these 64 Interview Questions for some help.

58. Tell us a little bit about yourself.
My name is Thanh Nguyen. I came here from vietnam 12 years ago. I went to kaimuki High for 2 years and get a diploma from there. Then i got into KCC majoring in IT. Got my degree in 2009 along with 3 certifications that i obtain from KCC. Then i took one year break then transferred to UH west Oahu. I got my BA in IT in may 2013. I am currently looking for a job in the IT field.

59. What are your greatest strengths?
I am punctual, flexible, opened minded, and hard-working, and flexible. I can adapt to any situation or work atmosphere.

60. What are your greatest weaknesses?
I am very direct. i tend to speak up my mind. When hearing something wrong, there is no way i would just keep listening. Sometimes, it really back fire because not everyone appreciate honesty. especially when it's against their belief.So I sometimes hurt people unintentionally.

61. What do you like about your current job or what did you like about your last job?
The last job is had was very fast pace. Its was in the restaurant industry. Its more physically demanding. It's just something that doesn't interest me at first. But as i started working, i learned many things such as customer service, how to be a team player.

62. Give us an example of when you handled a stressful situation.
I think the best way is to keep focusing on the job. That's will help you keep away the stress. If I always think this is too hard and keep on stressing, i will never get anything done. 

62. Give us an example of one of the toughest problems you had to face, and how did you deal with it?
One time, i had to deal with a customer complaining about the food not the same as the other locations. I told that person because the chefs are different. they have different style of cooking. for some reason he got mad at me and want to talk to the manager.

63. Why do you think you should get this position?
Considering my IT background and all the techniques, and skills that i learned in school.  I feel that job description fits me perfectly. I think i have what it takes to do the job

64. Do you think you are the best person for this job? If so, why? (why should we hire you)
First, I am very punctual. I don' like to wait for people when they are late. Therefore, I just can not do the same thing to you.
Second, I am flexible. I will be able to adapt to any working environment
third, i am hard-working. I always try my best when doing something.
fourth, i am open-mined. I am always opened to the new idea. And when i am doing something wrong, i like my coworker to tell me so that i can learn from my mistake.

65. Why did you apply for this position?

66. Why did you apply for a position with our company and what do you know about us?
IT is the field that i am really interested in. From the technical skills that i learned in school and during my internship, I think i can offer that knowledge to your company.
H&R is a big company, therefore you the working environment is fast-paced. I like to work n fast paced environment because it keep me from distracting.

67. Why should we hire you?
I have what it take to do the job

68. Tell us about your short and long term goals?
my short term goal is to obtain this IT position. And my long term goal will be growing with the company and obtaining a higher position in  the company

69. Where do you see yourself five years from now?
i see myself growing with the company. Hopefully by then, i can obtain higher position 

70. Please explain, what does customer service mean to you?

Finding out exactly what the customer is looking for and doing your best to assist them

71. What does being a team player mean to you?
team player mean working and cooperating with others to reach a specific goal. 

72. Give us an example of how you handled a conflict with another employee?
First i will try to remain calmed. Then I will try to talk to that person to find out if there is any misunderstanding. I'll try my best to be reasonable and rational the other party. IF there is any misunderstanding I'll try to sort it out. 

73. What are your salary expectations?
I am expecting somewhere from maybe 10-15 /hour. Even though i got a BA but this is my first IT job if i got hired, so i don't really have any high expectation for the salary. 

74. What would you consider your most important accomplishment?

75. How would you define success?
For me, success is the feeling of satisfaction when I accomplished my goal. 

76. At your last review, what improvements did your manager suggest you make?

77. What would your coworkers say about you?
They gonna say something like friendly, hardworking, and open-minded.