Most common latest interview questions with answers (2010/2011)

Most common latest interview questions with answers (2010/2011)

(Technical questions expected in all interviews – for system admin/ IT administrator and other jobs related to IT networking)

1.       Port number for SMTP? The answer is port number 25.

One of the most common interview questions is SMTP port number. As per my experience most of the interviewers asked me the same (May be the first question). Everyone wonder how this question related to the job. But this question is testing your experience with firewall. How? Because every company uses some kind of mail server (Exchange or other mail server), in order to allow the messaging communication between internal company to external world, this port number plays important role. So everybody must aware of this question.

2.       What does ARP do? – ARP used to map IP address to respective MAC address.

This looks very simple, but many people answered wrongly. Most of answer would be ‘ARP converts IP to MAC’ which is completely wrong. So think twice before answer this question. Why? Answer is in next.

3.       What is DNS? (Forward DNS and reverse DNS) – DNS (Domain Naming Service) which translates host name to IP. Host name could be URL, domain name or FQDN (Fully Qualified Domain Name) of any physical/virtual machine. Reverse DNS translates IP to hostname.

Here is confusion between DNS and ARP. ARP is a layer 2 protocol which deals with Data link layer characteristics (Ex. MAC address). DNS is layer 7 application protocol, only deals with configured information in application (Ex deals with DNS SERVER).

4.       Another port number question: what is the port number for SSH? Answer is 22.

Be careful when answering this question, the interviewer may confuse you with HTTPs port number (443). We might think the answer may be 443, because both port numbers are using secure connection. HTTPs is for secure connection to the website where as SSH provides secure channel (secure communication and file transfer) between two points in network.

5.       Port number for FTP – 20 and 21. 20 for data 21 for control

6.       What is command to view IP details in windows machine and Linux machine?

IPconfig – command for listing all interface details in windows and ‘ifconfig’ for linux.

7.       What are commands associated with IPCONFIG command?

Ipconfig/release

Ipconfig/renew

Ipconfig/flushdns

8.       What is network gateway?

Network gateway is the entry or exit point for any network and connects two different networks. This gateway can be either hardware based or software based or both.

9.       What is subnet mask?

Subnet mask is used to identify network address and host address. In other words it separates network and host ID from IP address.

10.   What is an IP address and format of IPv4 address? IP address is an identifier for every device in network. IP address consists of 4 octets, each octet having 8 bits and in total there are 32 bit addresses are available. So IPv4 is having total of 2³² addresses and it’s a 32 bit address and IPv6 is 64 bit address.

11.   You can expect a question from subnetting? E.x In a given network configuration, 192.168.4.34/28. How many usable subnets are in this network? Whatever the mask value, Just subtract the mask value from 32 and you will get 2⁴ = 16. So there are 16 usable subnets are available.

12.   What is VLAN? VLAN is used to divide large network into smaller sub systems. In VLAN computer/devices separated by logical groups.

13.   What is the purpose of SYSVOL folder in windows server? SYSVOL is the shared folder which provides standard location to store important elements of group policy objects (GPO) and scripts so that all stored information replicated to domain controller.

14.   Server 2003/2008 FSMO roles?

FSMO – Flexible Single Mode Operation roles of windows server are

1.       Schema master – controls all updates to schema within the forest. There should a single schema master for entire forest

2.       Domain naming master – responsible for creation and deletion of domains in the forest.

3.       Infrastructure master – updates reference from objects within its domain with objects in other domain.

4.       RID Relative ID master – manages security Identifier for every objects.

5.       PDC emulator – advertise as primary domain controller, provides compatibility for Windows NT backup domain controllers. Also maintains latest user passwords.

15.   Port number for SQL server? What port you should open in the firewall to allow sql server communications? Port number for SQL server is 1433.

16.   Port number for DHCP server and DHCP client?

DHCP server port number is 67 and DHCP client reply port number is 68.

17.   Candidates can expect a scenario relate question? Interviewer describes any scenario and wants you to explain your answer?

Ex. Can two different networks or domain communicate with each other by windows XP as gateway? Assume that there is two different networks/domains are in the network. In between, one Windows machine is configured as gateway. Is it possible to have a computer as a gateway? If yes please justify your answer.

Yes, it’s possible to configure a computer as a gateway. That computer must have two NIC’s assigned with two different IP addresses. And enable static routing protocol (RIP) in the computer and add the routes by manually.

18.   What is default gateway?

Default gateway connects the machine to outside world. More often default gateway connects computer to the internet.

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