Dhcp interview questions and Answers

1) What is dhcp?

Dynamic Host Configuration Protocol (DHCP) is a network protocol that enables a server to automatically assign an IP address to a computer from a defined range of numbers (i.e., a scope) configured for a given network.

2) What is the use for DHCP?

A: DHCP is used for the DHCP servers, personal computers can get their configuration from a DHCP server on an IP configuration. The server knows nothing about the personal computers until they make a request for information. Usually the most

Common information sent is IP address and DHCP is used to make a large network administration easier.

3) What is the dhcp process for client machine?

Ø   A user turns on a computer with a DHCP client.

Ø   The client computer sends a broadcast request (called a DISCOVER or DHCPDISCOVER), looking for a DHCP server to answer.

Ø  The router directs the DISCOVER packet to the correct DHCP server.

Ø  The server receives the DISCOVER packet. Based on availability and usage policies set on the server, the server determines an appropriate address (if any) to give to the client. The server then temporarily reserves that address for the client and sends back to the client an OFFER (or DHCPOFFER) packet, with that address information. The server also configures the client’s DNS servers, WINS servers, NTP servers, and sometimes other services as well.

Ø   The client sends a REQUEST (or DHCPREQUEST) packet, letting the server know that it intends to use the address.

Ø   The server sends an ACK (or DHCPACK) packet, confirming that the client has a been given a lease on the address for a server-specified period of time.

4) What ports are used by DHCP and the DHCP clients?
Requests are on UDP port 68, Server replies on UDP 67

5)  What does a Super Scope do in DHCP?

A: The Super Scope gives the DHCP server the possibility to have leases to multiple clients on the same physical network. The leases come from multiple scopes. All scopes must be defined using DHCP manager before the Super Scope creation and they are named member scopes. The DHCP problems can be resolved by the Super Scope in different ways like the following:

a) On a physical network like a LAN network where multiple logical IP networks exist Super

Scope is very useful here. These types of networks are also named martinets.

b) There is also need for a Super Scope when the address pool for the current scope becomes empty and there is a need for new computers on the physical network.

c) When clients have to move on another scope.

d) When DHCP clients from the other side of the relay agents (BOOTP) or the network has many logical subnets.

e) When standard networks are limited to leasing addresses for the clients.

6) Q: How can we switch the roles in an Active Directory?

A: Switching or transferring roles in an Active Directory can be made with the use of

Ntdsutil.exe.

7) What is the purpose of a Stub zone DNS?

A: The copy of a zone that has only the needed resources for finding the authoritative DNS servers in that specific zone (DNS= Domain Name Servers) is called a Stub zone. It also resolves names for DNS namespaces, thing required when names must be resolved from two

different DNS namespaces. The Stub zone contains: the master server’s IP that is used for updating the Stub zone and the SOA (Start of Authority), the NS (name server) and the glue A delegated zone records.

8) What main file is used for Active Directory backup and how it is made? A: Active Directory backup is made using NTbackup utility. The backup is made once with the system state and they are restored also together because they depend on each other. The system state has different components like:

a)    The registry

b)    Boot files or startup files (files required by the operating system to start). c)    The component services

d)       The system volume or the SYSVOL folder this is a folder that contains files that are shared on a domain.

e)    The Active Directory

9) Does a windows administrator have to be critical?

A: Yes and I can explain how. A system administrator is responsible for an entire network which means he/she must take care of multiple things in the same time which is not an easy task. In order to achieve this, an administrator must have high organization skills and a high technical knowledge and he/she must prevent the problems from happening so that he/she won’t have to be forced to fix them.

7. Q: In what way is forward lookup zone different from the reverse lookup zone in NDS?

A: There is one difference between these two: the forward lookup means name to IP and reverse lookup means IP to name.

10) As a system administrator can you make backup and recovery of data?

A: This is a responsibility that any system administrator must have assume as a basic skill. Of course there are many types of backup that can be made but all must be known for a successful career.

11) What is the meaning of DHCP and what is the port used by it to work? A: DHCP or Dynamic Host Configuration Protocol has the ability to assign an IP automatically; this is done in fact by the server and has a number range. When the system starts an IP is assigned automatically. The DHCP server has port number 68, while the client has 67.

12) Can you ensure an updated system all the time and perform market research?

A: Staying up-to-date is another strong point of a professional administrator, technology

evolves and we must keep up with the flow, otherwise we can’t do our job in a professional way. Market research is the key to an up-to –date work.

13) Is it possible for a computer to be able to browse the internet without having a default gateway?

A: Yes it is as long as we use a public IP address. The gateway is required as a router or firewall when using an intranet address.

14) What are the advantages or disadvantages   of using DHCP?

A: The advantage is that the DHCP server configures all IP’s automatically and the disadvantage is that when you receive a new IP address the machine name remains the same

15) Describe the integration between DHCP and DNS?
Traditionally, DNS and DHCP servers have been configured and managed one at a time. Similarly, changing authorization rights for a particular user on a group of devices has meant visiting each one and making configuration changes.

DHCP integration with DNS allows the aggregation of these tasks across devices, enabling a company’s network services to scale in step with the growth of network users, devices, and policies, while reducing administrative operations and costs. This integration provides practical operational efficiencies that lower total cost of ownership.

Creating a DHCP network automatically creates an associated DNS zone, for example, reducing the number of tasks required of network administrators. And integration of DNS and DHCP in the same database instance provides unmatched consistency between service and management views of IP address-centric network services data.

16) List some Benefits of using DHCP
DHCP provides the following benefits for administering your TCP/IP-based network:
Safe and reliable configuration. DHCP avoids configuration errors caused by the need to manually type in values at each computer. Also, DHCP helps prevent address conflicts caused by a previously assigned IP address being reused to configure a new computer on the network.
Reduces configuration management.

Using DHCP servers can greatly decrease time spent to configuring and reconfiguring computers on your network. Servers can be configured to supply a full range of additional configuration values when assigning address leases. These values are assigned using DHCP options. Also, the DHCP lease renewal process helps assure that where client configurations need to be updated often (such as users with mobile or portable computers who change locations frequently), these changes can be made efficiently and automatically by clients communicating directly with DHCP servers.

because of its association with the IP. It’s not a real problem but when somebody tries to access the machine by its name it become one.

13. Q: Are you familiar with monitoring?

A: Yes, monitoring is a base activity of a system administrator, he/she manages all the access rights and the server space, security of the user accounts is one of the most important things here. Also an administrator must make sure that the user’s activity doesn’t affect in any way the integrity of the server.

14. Q: How can we create a SRV record in DNS?

A: To do this we must open the DNS then we must select the abc.local domain the right click and we must go to Other New Records and the SRV ( choose location).

15.Q: In how much time are the security changes applied on the domain controllers?

A: Including policies for personal and public lockout, the changes apply immediately. The changes also include passwords and LSA or Local Security Authority.

16. Q: What do you do if a an end user states that a file is gone?

A: Files are deleted constantly by end users but the backup can restore them. Anyhow before using the backup we must check if the user didn’t move the file by mistake in another place.

17. Q: Where is the storage place of the environmental settings and documents from the roaming profile?

A: These documents and settings are deposited locally until the user’s log off, when they are moved into the shared folder from the server so the log on at a fresh system may take a while because of this.

19. Q: When is a good time for creating a forest?

A: Certain companies that have different bases require different trees and separate namespaces. And unique names sometimes give birth to different identities of DNS. Also companies are sometimes acquired and get under other influences but the continuity must be preserved for the names.

20. Q: Can you explain to us about you experience in the past regarding windows administration?

A: I have ten years of experience in this field, I was passionate about computers since childhood and I installed many operating systems at home and inside organizations including these versions of windows: 95, 98, 98 SE, NT, Millennium, 2000, 2003 Server, XP, Seven, Vista. I also managed these systems and performed maintenance; I worked with different applications from the windows environment.

21. Q: How can you handle a situation in which for instance if you have an application that is not running on Windows 2003 because it’s older?

A: In this situation the application has to be started in the compatibility mode with a

previously windows operating system. This is made by right clicking the application icon and choosing another Windows from the compatibility menu.

22. Q: What is the meaning of Repadmin.exe from Windows Server 2008?

A: Repadmin.exe means Replication Diagnostics Tool and helps for the diagnostic of domain controllers in the Windows system. This tool is used by administrators to see the replication topology from the perspective of every domain controller. The active Directory forest can

also be supervised by Repadmin.exe and replication problems can be tracked.

23. Q: What difference can we find in the usage of CSVDE versus LDIFDE? A: CSVDE and LDIFDE are both commands and are used for importing and exporting objects but they are different in the way that CSVDE uses the format CSV (Comma Separated Value) which is an Excel file for files and LDIFDE uses LDIF (LDAP Data Interchange Format) file type which can be viewed with a simple text editor. LDIFDE can be also used for editing or deleting objects unlike CSVDE.

24. Q: What big differences exist between these two operating systems: Windows 2000 and Windows XP?

A: Windows 2000 has more capabilities than Windows XP especially regarding features like DHCP, Terminal Services or DNS. It has all the advantages for server usage. Windows 2000 is a little more professional than XP, but they are both coming with different versions for every user taste. While XP has Home version, Professional or Enterprise, Windows 2000 has Professional and Server editions. The Home version of XP comes with minimal features because the target clients are beginners.

25. Q: What are the things that make UNIX different from Windows?

A: The code loading runtime of UNIX is different from the one that Windows has. We must become aware of how the system exactly works before we make a dynamically loading module. UNIX has the shared objects with the .so extension that encapsulate lines of code that the programs will use and the functions names. These function names become the references of those functions in the memory of the program when the file is combined with the program. In Windows the .dll file (dynamic-link library file) doesn’t have references and the code of the files does not link to the memory of the program but they get through a lookup table which points to data or functions. UNIX has just one type of library file, with the

.a extension and the code of many object file is contained within with the .o extension. When the link is created for a shared object file the definition of the identifier may not be found, so the object code from the library will be included.