Monday, January 2, 2012

Network Engineer Interview Questions and Answers

Interview Questions

A) Tell me something about yourself.
Tell about your eductaion, place you belong to, some struggle in life which shows that you have positive attitude and will to fight the odds.

B) Technical Questions:

1) What are the types of LAN cables used? What is a cross cable?
Types of LAN cables that are in use are "Cat 5" and "Cat 6". "Cat 5" can support 100 Mbps of speed and "CAT 6" can support 1Gbps of speed.
Cross cable: Its used to connect same type of devices without using a switch/hub so that they can communicate.

2) What is the difference between a normal LAN cable and cross cable? What could be the maximum length of the LAN cable?
The way the paired wires are connected to the connector (RJ45) is different in cross cable and normal LAN cable.
The theoritical length is 100 meters but after 80 meters you may see drop in speed due to loss of signal.

3) What id DHCP? Why it is used? What are scopes and super scopes? DHCP: Dynamic host configuration protocol. Its used to allocate IP addresses to large number of PCs in a network environment. This makes the IP management very easy.
Scope: Scope contains IP address like subnet mask, gateway IP, DNS server IP and exclusion range which a client can use to communicate with the other PCs in the network.
Superscope: When we combine two or more scopes together its called super scope.

4) What are the types of LAN cables used? What is a cross cable?
Types of LAN cables that are in use are "Cat 5" and "Cat 6". "Cat 5" can support 100 Mbps of speed and "CAT 6" can support 1Gbps of speed.
Cross cable: Its used to connect same type of devices without using a switch/hub so that they can communicate.

5) What is Active Directory?
A central component of the Windows platform, Active Directory directory service provides the means to manage the identities and relationships that make up network environments. For example we can create, manage and administor users, computers and printers in the network from active directory.

6) What is DNS? Why it is used? What is "forward lookup" and "reverse lookup" in DNS? What are A records and mx records?
DNS is domain naming service and is used for resolving names to IP address and IP addresses to names. The computer understands only numbers while we can easily remember names. So to make it easier for us what we do is we assign names to computers and websites. When we use these names (Like the computer uses DNS to convert to IP address (number) and it executes our request.
Forward lookup: Converting names to IP address is called forward lookup.
Reverse lookup: Resolving IP address to names is called reverse lookup.
'A' record: Its called host record and it has the mapping of a name to IP address. This is the record in DNS with the help of which DNS can find out the IP address of a name.
'MX' Record: its called mail exchanger record. Its the record needed to locate the mail servers in the network. This record is also found in DNS.

7) What is IPCONFIG command? Why it is used?
IPCONFIG command is used to display the IP information assigned to a computer. Fromthe output we can find out the IP address, DNS IP address, gateway IP address assigned to that computer.

8) What is APIPA IP address? Or what IP address is assigned to the computer when the DHCP server is not available?
When DHCP server is not available the Windows client computer assignes an automatic IP address to itself so that it can communicate with the network cmputers. This ip address is called APIPA. ITs in the range of 169.254.X.X.
APIPA stands for Automatic private IP addressing. Its in the range of 169.254.X.X.

9) What is a DOMAIN? What is the difference between a domain and a workgroup? Domain is created when we install Active Directory. It's a security boundary which is used to manage computers inside the boundary. Domain can be used to centrally administor computers and we can govern them using common policies called group policies.
We can't do the same with workgroup.

10) Do you know how to configure outlook 2000 and outlook 2003 for a user?
Please visit the link below to find out how to configure outlook 2000 and outlook 2003.

11) What is a PST file and what is the difference between a PST file and OST file? What file is used by outlook express?
PST file is used to store the mails locally when using outlook 2000 or 2003. OST file is used when we use outlook in cached exchanged mode. Outlook express useds odb file.

12) What is BSOD? What do you do when you get blue screen in a computer? How do you troubleshoot it?
BSOD stands for blue screen of Death. when there is a hardware or OS fault due to which the windows OS can run it give a blue screen with a code. Best way to resolve it is to boot the computer is "LAst known good configuration". If this doesn't work than boot the computer in safe mode. If it boots up than the problemis with one of the devices or drivers.

13) What is RIS? What is Imaging/ghosting?
RIS stands for remote installation services. You save the installed image on a windows server and then we use RIS to install the configured on in the new hardware. We can use it to deploy both server and client OS. Imaging or ghosting also does the same job of capturing an installed image and then install it on a new hardware when there is a need. We go for RIS or iamging/ghosting because installing OS everytime using a CD can be a very time consuming task. So to save that time we can go for RIS/Ghosting/imaging.

14) What is VPN and how to configure it?
VPN stands for Virtual private network. VPN is used to connect to the corporate network to access the resources like mail and files in the LAN. VPN can be configured using the stepsmentioned in the KB:

15) Your computer slowly drops out of network. A reboot of the computer fixes the problem. What to do to resolve this issue?
Update the network card driver.

16) Your system is infected with Virus? How to recover the data?
Install another system. Insall the OS with the lates pathces, Antivirus with latest updates. Connect the infected HDD as secondary drive in the system. Once done scan and clean the secondary HDD. Once done copy the files to the new system.

17) How to join a system to the domain? What type of user can add a system to the domain?
Please visit the article below and read "Adding the Workstation to the Domain"

18) What is the difference between a switch and a hub?
Switch sends the traffic to the port to which its meant for. Hub sends the traffic to all the ports.

19) What is a router? Why we use it?
Router is a switch which uses routing protocols to process and send the traffic. It also receives the traffic and sends it across but it uses the routing protocols to do so.

20) What are manageable and non manageable switches?
Switches which can be administered are calledmanageable switches. For example we can create VLAN for on such switch. On no manageable swiches we can't do so.

21. What is NIC?
A network card, network adapter or NIC (network interface controller) is a piece of computer hardware designed to allow computers to communicate over a computer network

22. What is USB?

Universal Serial Bus (USB) is a serial bus standard to interface devices. Devices like Modem, Mouse, Keyboard etc can be connected.

23. Dialup vs. Broadband

A broadband connection (ADSL) provides high-speed Internet access over a standard phone line. The advantage of a broadband connection over a standard dialup service, is that Broadband is considerably faster, and is "always-on", meaning that once you"re logged on, your PC is online until the PC is turned off again.

Broadband offer high-speed Internet access and allows telephone calls and a permanent Internet connection to share a single phone line simultaneously whereas in Dialup connection either Internet connection or telephone call can made at given time.

24. LAN and WAN

A local area network is a computer network covering a small geographic area, like a home, office, or group of buildings

Wide Area Network (WAN) is a computer network that covers a broad area (i.e., any network whose communications links cross metropolitan, regional, or national boundaries). Or, less formally, a network that uses routers and public communications links

25. Microsoft Access

Microsoft Office Access, previously known as Microsoft Access, is a relational database management system from Microsoft.

26. What is RAS?

Remote Access Services (RAS) refers to any combination of hardware and software to enable the remote access to tools or information that typically reside on a network of IT devices.

27. Difference between Client Mail and Web Mail?

Email clients download your emails onto your computer. Using a specialized email program such as Outlook Express or Apple Mail has the advantage of giving you complete control over your email; every email you receive is placed on your computer and you can keep as many large file attachments as you want.
Checking your email through our webmail is similar to using Hotmail or Yahoo! Mail. You never actually copy your messages to your computer; in fact, you are looking at them through your web browser on somebody else"s computer. When you are not online, you are not able to see your email.

28. RAM and ROM

random access memory, a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.

Pronounced rahm, acronym for read-only memory, computer memory on which data has been prerecorded. Once data has been written onto a ROM chip, it cannot be removed and can only be read. Unlike main memory (RAM), ROM retains its contents even when the computer is turned off. ROM is referred to as being nonvolatile, whereas RAM is volatile.

29. Spamguard

Spam Guard is an Outlook add-in that filters email that arrives in your inbox. If the sender of any message cannot be identified then the message is moved into a spam quarantine folder. Messages deposited in the spam quarantine folder can be inspected and either deleted or approved at your leisure.

30. Firewall and Antivirus
A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.

Antivirus is a software program which helps protect a computer against being infected by a virus.

31. DNS

Short for Domain Name System (or Service or Server), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they"re easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name might translate to

32. IPConfig

IPConfig is a command line tool used to control the network connections on Windows NT/2000/XP machines. There are three main commands: "all", "release", and "renew". IPConfig displays all current TCP/IP network configuration values and refreshes Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS) settings. Used without parameters, IPConfig displays the IP address, subnet mask, and default gateway for all adapters.

33. Trace route

Trace route is the program that shows you the route over the network between two systems, listing all the intermediate routers a connection must pass through to get to its destination. It can help you determine why your connections to a given server might be poor, and can often help you figure out where exactly the problem is. It also shows you how systems are connected to each other, letting you see how your ISP connects to the Internet as well as how the target system is connected.

1) What is IP Address ?

2) What are the layers of network ?

3) What are the different types of network ?

4) What is networking ?

5) What is the difference between OSI and TCP/IP Model ?

6) What is TCP/IP ?

7) What is HTTP?

8) What is Protocol ?

9) What is communication medium ?

10) What is PORT ?

11) What is SOCKET ?

12) What is the difference between PORT and SOCKET?

13) What is wireless networking ?

14) What is topology ?

15) What are the different types of topology ?

16) What is the size of IP Address?

17) What is FTP ?

18) What is SMTP ?

19) What are the different types of protocol ?

20) What is Dial-Up connection ?

21) What is Broad Band Connection?

22) What is the difference between Dial-up and broad band connection?

23) What IEEE standard for wireless networking?

Ans: 802.11g

24) What is IEEE standard ?

Ans: Institute of electrical and electronic engineer.They develop standard for networking