Deploying and Configuring the DHCP Service

What is the main dis-advantage of a centralized DHCP infrastructure?

Traffic congestion Single point of failure

A client has reached T1 in its lease time of an IP address. What amount of time does this equate to on the client

50% of the lease time. Typically leases last 8 days, so T1 would be 4 days into the lease

What port does DHCP use on the server

67

What port does DHCP use on the client

68

What time value does T2 represent?

87.5 of the lease time

Choose the letter that corresponds to the best answer. More than one answer choice may achieve the goal. Select the BEST answer. What servers should not be DHCP clients? a. Web servers, DHCP servers, and domain controllers b. Workstations c. End user laptops d. Computers, which might have IP addresses in the exclusion range

A

The following is a hexadecimal address that is uniquely associated with a specific Network Interface Card (NIC): a. MAC b. JET c. BOOTP d. IETF

A

Which of the following DHCP infrastructure designs requires the largest number of DHCP server implementations? a. hybrid b. centralized c. dynamic d. distributed

A The options C and D are none existent, whilst A offers the least.

For a stand-alone DHCP server to lease IP addresses what action must an administrator take

Authorise it. In the DHCP snap-in, right click and select Authorise

Give 2 advantages of a distributed DHCP structure? Give a dis-advantage of a distributed DHCP structure

Advantages: Your clients have ready access to their DHCP servers. You do not have to worry about DHCP traffic adding to the burden of your routers, because all the client/server traffic is local. Dis-advantages: The potential disadvantage of this arrangement is the need to install and configure a large number of DHCP servers. This is especially true if you plan to have multiple servers on each subnet for fault tolerance

A client fails to obtain a lease and returns to its init state (ie without an IP address), what happens next?

All TCP/IP communication then ceases, except for the transmission of DHCPDISCOVER broadcasts.

If a client is in the 'init' stage of DHCP negotiation what is its IP configuration?

At this stage it has no IP address. This is typical of the client as it boots for the first time on the network

Why must a DHCP server be placed on every subnet?

Because DHCP clients broadcast for a request in the discovery phase and broadcasts cannot go beyond the router

The following is an administrative grouping of scopes that is used to support multiple logical subnets on a single network segment: a. host b. scope c. superscope d. multinet

C

Which of the following DHCP message types is sent first in process of obtaining an address lease? a. DHCPOFFER b. DHCPACK c. DHCPDISCOVER d. DHCPREQUEST

C

Which of the following is not one of the techniques you can use to provide fault tolerance for DHCP servers? a. splitting scopes b. using stand-by servers c. DHCP servers using identical scopes d. failover clustering

C

Which of the following types of DHCP address allocation is the equivalent of a reservation in Windows Server 2012? a. dynamic allocation b. automatic allocation c. manual allocation d. hybrid allocation

C

At which layer of the OSI model does DHCP operate? a. Session layer b. Network layer c. Application layer d. Presentation layer

C Take note

Microsoft recommends as good practice dthat a DHCP server should itself be a DHCP client. True or False

False The DHCP server must have a static address

DHCP uses TCP as its transport protocol. True or False?

False. It uses UDP

Choose the letter that corresponds to the best answer. More than one answer choice may achieve the goal. Select the BEST answer. To make use of Pre-boot Execution Environment (PXE) and Windows Deployment Services (WDS), what special configuration do you require on the server and client? a. The client must have a special PXE-enabled network adapter. b. Both client and server are capable by default. c. The client and server both require some preparatory configuration. d. The DHCP server on the network must have a custom PXEClient option (option 60) configured with the location of the WDS server on the network.

D

Which of the following message types is not used during a successful DHCP address assignment? a. DHCPDISCOVER b. DHCPREQUEST c. DHCPACK d. DHCPINFORM

D

What is a distributed DHCP infrastructure?

DHCP servers are placed on each subnet

When a client issues a DHCPREQUEST, it is trying to lease an IP address. True or False

False. The client is in fact responding to ACCEPT an address offered to it by the server

What are the 8 message types DHCP defines?

DHCPDISCOVER: Used by clients to request configuration parameters from a DHCP server • DHCPOFFER: Used by servers to offer IP addresses to requesting clients • DHCPREQUEST: Used by clients to accept or renew an IP address assignment • DHCPDECLINE: Used by clients to reject an offered IP address • DHCPACK: Used by servers to acknowledge a client's acceptance of an offered IP address • DHCPNAK: Used by servers to reject a client's acceptance of an offered IP address • DHCPRELEASE: Used by clients to terminate an IP address lease • DHCPINFORM: Used by clients to obtain additional TCP/IP configuration parameters from a server

What are the three DHCP allocation methods?

Dynamic Automatic Manual

Explain manual allocation

In the Windows Server 2012 DHCP server, manually allocated addresses are called reservations. Listen up Use manually allocated addresses for computers that must have the same IP address at all times, such as Internet web servers that have specific IP addresses

What is the Powershell command to install the DHCP role?

Install-WindowsFeature DHCP [-ComputerName <computer_name>]

Are the DHCP options offered by Microsoft proprietary?

No. RFC 2131

What does PXE stand for and what is its importance

Pre-boot Execution Environment Pay attention....... (PXE) is a feature built into many network interface adapters that enables them to connect to a DHCP server over the network and obtain TCP/IP client settings, even when the computer has no operating system. Administrators typically use this capability to automate the operating system deployment process on large fleets of workstations. In addition to configuring the IP address and other TCP/IP client settings on the computer, the DHCP server can also supply the workstation with an option specifying the location of a boot file that the system can download and use to start the computer and initiate a Windows operating system installation. A PXE-equipped system downloads boot files using the Trivial File Transfer Protocol (TFTP), a simplified version of the FTP protocol that requires no authentication.

What is a manual allocated IP in DHCP also called

Reservation Pay attention While DHCP is an excellent TCP/IP configuration solution for most computers on a network, it is not such a good solution for a few components. Domain controllers, Internet web servers, and DHCP servers themselves need static IP addresses. Although the IP address for a client could be manually created on the client, the reason for putting it in DHCP is so that a 'central' record is created and accessible to all admins, without a risk of conflict occuring on the network

What are the two types of scopes offered by DHCP?

Server options Scope options Pay attention Scope options: Supplied only to DHCP clients receiving addresses from a particular scope (eg gateway address) Server options: Supplied to all DHCP clients receiving addresses from the server (eg DNS address).

What is a centralized DHCP infrastructure?

Single DHCP server with relay agents to manage requests for subnets Pay attention Most IP routers have DHCP relay agent capabilities built into them. If the routers connecting your subnets are so equipped, you can use them as relay agents, eliminating the need for a DHCP server on each subnet. If your routers cannot function as DHCP relay agents, you can use the relay agent capability built into the Windows server operating systems. In Windows Server 2012, the DHCP relay agent capability is built into the Remote Access role.

Explain dynamicallocation

The DHCP server assigns an IP address to a client computer from a scope for a specified length of time.

Explain automatic allocation

The DHCP server permanently assigns an IP address to a client computer from a scope. Automatic allocation is essentially dynamic allocation with an indefinite lease.

What is the 'magic cookie'?

The Options field in DHCP can contain many options, which would be impractical to define for each client The Options field informs the server about what is contained in the rest of the field. Listen up The magic cookie is a 4-byte subfield containing the dotted decimal value 99.130.83.99

What happens on the client when T2 is reached

The client re-enters the 'binding state'. In practical terms, this means it begins the process of DORA - requesting an answer from ANY DHCP server

What is a DHCPNACK?

This is where the DHCP server sends a negative acknowledgement to the client that has requested an address If this happens, the client must initiate DORA

What is the DHCP overload option?

This uses a so called 'overflow' field, that utilises the redundant sname and or file fields if the option packet is over 576 bytes in length. Pay attention Because User Datagram Protocol (UDP) datagrams carry DHCP messages, the packets are limited to a maximum size of 576 bytes, and the inclusion of a large number of options can test this limit. Because the DHCP message's sname and file fields are rarely used today, the DHCP standard allows these fields to be used to contain options that do not fit in the standard options field.

Member servers that have the DHCP role installed do not need to be authourised as this happens automatically. True or False

True Pay attention When you install the DHCP Server role on a computer that is a member of an AD DS domain, the DHCP Server is automatically authorized to allocate IP address to clients that are also members of the same domain (page 313)

What is WDS

Windows Deployment Services Pay attention Windows Deployment Services (WDS), enables you to manage image files that remote workstations can use to start up and install Windows. For a PXE adapter to access WDS images, the DHCP server on the network must have a custom PXEClient option (option 60) configured with the location of the WDS server on the network.

Choose the letter that corresponds to the best answer. More than one answer choice may achieve the goal. Select the BEST answer. You are preparing to deploy Windows 8 to a large number of new workstations. Which of the following options would be best? a. Install Windows 8 using Pre-boot Execution Environment (PXE) and Windows Deployment Services (WDS). b. Delegate the work to a team of local administrators to divide up. c. Manually install the operating system yourself. d. Manually configure each workstation's IP address.

a

Choose the letter that corresponds to the best answer. More than one answer choice may achieve the goal. Select the BEST answer. Your DHCP servers are burdened with heavy traffic, most related to IP address renewals. Unfortunately, virtually all the IP addresses in each of your subnets are allocated. Which of the following options is the best way to lower the renewal traffic? a. Increase the lease time. b. Deploy additional DHCP servers on the most burdened subnets. c. Shorten the lease time. d. Switch to manual allocation.

a

A DHCP client first attempts to reacquire its lease at half the lease time, which is known as: a. DHCP reservation b. T1 c. T2 d. DHCP lease

b

Which of the following network components are typically capable of functioning as DHCP relay agents? a. Windows 8 computers b. routers c. switches d. Windows Server 2012 computers

b

Choose the letter that corresponds to the best answer. More than one answer choice may achieve the goal. Select the BEST answer. One method a Dynamic Host Configuration Protocol (DHCP) server allocates IP addresses is called manual allocation. This process involves manually assigning an IP address to a particular server. What is the key benefit of DHCP manual allocation over manually configuring the address directly on the server? a. The DHCP server then contains a centralized list of permanently assigned addresses. b. The DHCP server might pass on more information than just an IP address. c. This process prevents accidental duplication of permanently assigned IP addresses. d. This manually assigned address is officially known as a reservation

c