Basic Network Administrator Interview Questions with Answers

1.What is a NIC?
Network Interface Card

2.What is a MAC Address?
MAC- Media Access Control .its a unique identifier defined for certain hardware/network adapters

3.When would you use a crosslink cable?
To link computers using this cable..You need to assign the static Ip if u need to

4.What are the main advantages and disadvantages of Fiber-Optic-based networks?
Adv:More efficient and quality of service is better.
Dis: Expensive, complicated

5.What is the difference between a Hub and a Switch?
Hub is device to connect two devices, switch is a network bridge which processes and routes data approximately over network layer of OSI Reference model

6.On which OSI layer can a router be found?
physical layer

7.What is CSMA/CD?
Carrier sense multiple access with collision detection

8.What is multicast?
to send data/info to group of computers using same network

9.What is Broadcast?
TO send data/info to all of the members of the network..( simple 176.16.255.255 for class B network)

10.What is the difference between TCP and UDP?
TCP-Transmission Control Protocol
UDP- user Datagram protocol

UDP is user assisted program and converts the application into the encapsulated form and makes it end point for data to send and then TCP helps in transmission or broadcast!


11.Describe some of the settings that are added by TCP and by UDP to the packet's header.

ans:Its called Encapsulation

12.What are TCP Ports? Name a few.
As described above End points are called Ports.
5/TCP,UDP   Remote Job Entry
7/TCP,UDP   Echo

13.What is a TCP Session?
the layer that establishes ,manages and terminates the session between two communticating devices

14.What three elements make up a socket?

Protocol (TCP, UDP or raw IP).
Local socket address (Local IP address and port number)
Remote socket address

15.What will happen if you leave the default gateway information empty while manually configuring TCP/IP?
i think it will automatically get it from DNS server

16.What will happen if you execute the following command: "arp –d *"?
- deletes all the ip address information

17.What is ICMP?
Internet Control Message Protocol

18.When would you use the ping command with the "-t" switch?
to get the ping back from other computer with no packet loss

19.What command-line tool would help you discover for which port numbers your computer is listening?
netstat -n  (on Dos prompt)

20.What is APIPA? How would you recognize it?
Automatic Private IP Addressing
for small network if u see something default automatic numeric values entered in a device that is attached you can see someone novice has done that using APIPA

21.What is a Cyclic Redundancy Check?
its a function that checks the input data value/length and than produces the output usualy of integral of 32 bits

22.What would you type in at a command prompt to view the IP settings for the computer that you are sitting at?
"ipconfig"


23.What command would you type in at a command prompt to view the IP address of the remote computer?
Ping
Netstat

24.What is the W Value for class B?

25.What is the Net ID of an IP Address of 18.9.25.3 with Subnet Mask of 255.0.0.0?
CLASS A network with NET ID 18.0.0.0

26.What is CIDR?
Classless Inter-Domain Routing

27.What is 255.255.255.255 used for?
Research

28.What is the maximum number of hosts for a Class B Network?
16384 (2(raise to power N)- 2)

29.What is the (default) class type of 195.152.12.1?
CLASS B with NET ID 195.152.0.0

30.What is the subnet mask for 10.0.10.1/17?
255.0.0.0

31.What is the result when changing from a subnet mask of 255.255.224.0 to a subnet mask of 255.255.240.0?
hmm..broadcast and binary address changes i guess

32.How can you access a shared folder from a remote computer? Name at least 3 methods.
-from ur pc my network place
- using a mapped drive
-Universal Naming Convention (UNC)