70-410 Lesson 11: DHCP

The DHCP server itself cannot be a DHCP client; it must have a static IPv4 address

Why is it necessary to exclude addresses from the range of addresses included in the scope?

b. Deploy additional DHCP servers on the most burdened subnets.

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.

The server responds with a DHCPNAK message to the client. Explanation: If the server cannot complete the assignment for any reason (for example, because it has already assigned the offered IP address to another system), it transmits a DHCPNAK message to the client, and the whole process begins again.

During DHCP lease negotiation, what happens if the client requests an IP address from the server but the server has already assigned the offered IP address?

b. T1

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

preboot execution environment (PXE)

A network adapter feature that enables a computer to connect to a server on the network and download the boot files it needs to run, rather than booting from a local drive.

Dynamic, automatic, and manual Explanation: The DHCP standards define three different IP address allocation methods: dynamic, automatic, and manual (reservations).

DHCP standards define multiple methods to allocate IP addresses. What are they?

centralized DHCP infrastructure

In Dynamic Host Configuration Protocol, a deployment model in which all of the DHCP servers are placed in a single location, such as a server closet or data center, and a DHCP relay agent is installed on each subnet, to enable the broadcast traffic on each subnet to reach the DHCP servers.

distributed DHCP infrastructure

In Dynamic Host Configuration Protocol, a deployment model in which at least one DHCP server is installed on each of the network's subnets.

dynamic allocation

In Dynamic Host Configuration Protocol, a method by which a DHCP server assigns an IP address to a client computer from a scope, or range of IP addresses, for a specified length of time.

manual allocation

In Dynamic Host Configuration Protocol, a method by which a DHCP server permanently assigns a specific IP address to a specific computer on the network.

automatic allocation

In Dynamic Host Configuration Protocol, a method by which a DHCP server permanently assigns an IP address to a client computer from a scope.

c. This process prevents accidental duplication of permanently assigned IP addresses.

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.

b. Computer boots up and begins broadcasting DHCPDISCOVER messages. d. DHCP servers reply with DHCPOFFER messages with an IP address and other TCP/IP configuration information. e. Computer selects an offer, broadcasting with a DHCPREQUEST message. c. DHCP server records the computer's information and responds with a DHCPACK message. a. Computer broadcasts an Address Resolution Protocol (ARP) message to ensure no other system is using the identical IP address. Explanation: The DHCP IP address assignment process can be summarized in packets: DHCPDISCOVER, DHCPOFFER, DHCPREQUEST, DHCPACK or DHCPNAK, ending with an ARP broadcast by the client to ensure it holds no duplicate IP address.

Order the steps that describe how DHCP clients get assigned an IP address. a. Computer broadcasts an Address Resolution Protocol (ARP) message to ensure no other system is using the identical IP address. b. Computer boots up and begins broadcasting DHCPDISCOVER messages. c. DHCP server records the computer's information and responds with a DHCPACK message. d. DHCP servers reply with DHCPOFFER messages with an IP address and other TCP/IP configuration information. e. Computer selects an offer, broadcasting with a DHCPREQUEST message.

a. MAC

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

Reservation In a Windows DHCP server, a manually allocated address is called a reservation.

What is another name for a manually allocated address by a Windows DHCP server?

Dynamic Host Configuration Protocol (DHCP)

A service that automatically configures the Internet Protocol (IP) address and other TCP/IP settings on network computers by assigning addresses from a pool (called a scope) and reclaiming them when they are no longer in use.

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. Explanation: Windows Server 2012 R2 includes a role called Windows Deployment Services (WDS), which 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.

2. To make use of Pre-boot Execution Environment (PXE) and Windows Deployment Services (WDS), what special configuration do you need on the server and client? a. The client must have a special PXE-enabled network adapter. b. Both the 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.

c. Application layer

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

A DHCP scope must be created and activated The DHCP server must be created and authorized. Explanation: A DHCP server must be authorized within the domain before it can hand out addresses. You must then create a scope and then activate the scope before the addresses defined within the scope can be leased out.

Before a DHCP server can hand out addresses, which steps must be completed (2)?

100 percent because dynamic address allocation requires periodic lease renewal messages whereas automatic does not Explanation: Automatic allocation reduces network traffic by eliminating the periodic lease renewal messages needed for dynamic allocation. In the Windows Server 2012 R2 DHCP server, automatic allocation is essentially dynamic allocation with an indefinite lease.

For DHCP address allocation, by how much is network traffic reduced related to periodic lease renewal messages when switching from dynamic allocation to automatic allocation?

Obtain an IP address automatically Explanation: In Windows computers, the DHCP client is enabled by default, although it is not mentioned by name in the interface. The Obtain an IP address automatically option in the Internet Protocol Version 4 (TCP/IPv4) Properties sheet and the Internet Protocol Version 6 (TCP/IPv6) Properties sheet controls the activation of the client for IPv4 and IPv6 respectively.

How are DHCP settings labeled in a Windows computer's network interface?

DHCPOFFER Explanation: All DHCP servers receiving the DHCPDISCOVER broadcast messages generate DHCPOFFER messages containing an IP address, and whatever other TCP/IP configuration parameters the server is configured to supply, and then transmit them to the client.

How do DHCP servers respond to a DHCPDISCOVER message?

In Windows Server 2012 R2, creating the scope is done separately, after adding the DHCP Server role. Explanation: In Windows Server versions prior to 2012, you can create a scope as you install the DHCP Server role. However, in Windows Server 2012 and Windows Server 2012 R2, the procedures are separate.

How does DHCP scope creation differ in Windows Server 2012 and Windows Server 2012 R2 compared to prior Windows Server versions?

The client sends a DHCPREQUEST message to all servers with the IP address of the chosen DHCP server. Explanation: After a specified time, the client stops broadcasting and signals its acceptance of one of the offered addresses by generating a DHCPREQUEST message, containing the address of the server from which it is accepting the offer along with the offered IP address, and then broadcasting it on the local network. This broadcast notifies the selected server that the client is accepting the offered address. It also notifies any other servers on the network that the client is rejecting their offers.

How does a DHCP client communicate which offered IP address it will accept from which DHCP server?

50 percent, or at 4 days into the lease Explanation: When the DHCP client reaches the 50 percent point of the lease's duration (called the renewal time value or T1 value), the client enters the renewing state and begins generating DHCPREQUEST messages and transmitting them as unicasts to the DHCP server holding the lease. DHCP clients also renew their leases each time they restart.

How far into the lease period does a DHCP client begin requesting renewal of the IP address?

Never Explanation: A DHCP server should not also be an active DHCP client. Before you install the DHCP Server role, be sure to configure the target server with a static IP address.

In what scenario should DHCP servers also be active DHCP clients?

c. In the Server Manager window, click Tools and then click DHCP. The DHCP console appears. a. Expand the server and IPv4 nodes. Right-click the IPv4 node and, from the context menu, select New Scope. The New Scope Wizard appears. Type a name for the scope into the Name text box and click Next. b. Configure IP address range, from starting to ending IP address. Configure the subnet mask. e. Configure the IP exclusion range, from starting to ending IP address. You can also specify a delay interval between the server's receipt of DHCPDISCOVER messages d. Specify the length of leases for the scope's addresses. Specify the default gateway, DNS, and activate the scope. Explanation: In Windows Server versions prior to 2012, you can create a scope as you install the DHCP Server role. However, in Windows Server 2012 and Windows Server 2012 R2, the procedures are separate. After installing the DHCP Server role, you must configure the service by creating a scope before it can serve clients.

Order the steps to create a DHCP scope. a. Expand the server and IPv4 nodes. Right-click the IPv4 node and, from the context menu, select New Scope. The New Scope Wizard appears. Type a name for the scope into the Name text box and click Next. b. Configure IP address range, from starting to ending IP address. Configure the subnet mask. c. In the Server Manager window, click Tools and then click DHCP. The DHCP console appears. d. Specify the length of leases for the scope's addresses. Specify the default gateway, DNS, and activate the scope. e. Configure the IP exclusion range, from starting to ending IP address. You can also specify a delay interval between the server's receipt of DHCPDISCOVER messages and its transmission of DHCPOFFER messages

a. In the Server Manager window, click Manage and then click Add Roles and Features. c. Leave the Role-based or feature-based installation radio button selected and click Next. d. Select the server on which you want to install the roles and/or features and click Next. b. Select the DHCP Server check box. An Add features that are required for DHCP Server dialog box appears. e. Click Next through to Confirm. Explanation: The DHCP Server service is packaged as a role in Windows Server 2012 R2, which you can install by using the Add Roles and Features Wizard, accessible from the Server Manager console.

Order the steps to deploy a DHCP server. a. In the Server Manager window, click Manage and then click Add Roles and Features. b. Select the DHCP Server check box. An Add features that are required for DHCP Server dialog box appears. c. Leave the Role-based or feature-based installation radio button selected and click Next. d. Select the server on which you want to install the roles and/or features and click Next. e. Click Next through to Confirm.

c. superscope

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

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.

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.

All the client/server network traffic is local, so minimal DHCP traffic on routers Clients have ready access to DHCP servers Explanation: A distributed DHCP infrastructure has distinct 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. 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.

What are the advantages of using a distributed DHCP infrastructure?

Pre-boot Execution Environment Explanation: The Pre-boot Execution Environment (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.

What does PXE stand for, describing a network adapter feature enabling a computer as a DHCP client even without an operating system?

The DHCP scope is the range of IP addresses on a subnet made available to DHCP clients. Explanation: A scope is a range of IP addresses on a particular subnet that a DHCP server has selected for allocation.

What is the DHCP scope?

Install-WindowsFeature DHCP [-ComputerName <computer_name>] Explanation: To install the DHCP Server role using PowerShell, use the Install-WindowsFeature DHCP [-ComputerName <computer_name>] syntax.

What is the PowerShell cmdlet and syntax for installing the DHCP Server role?

8 days Explanation: By default, the DHCP Server service in Windows Server 2012 R2 uses dynamic allocation, leasing IP addresses to clients for 8-day periods.

What is the default lease period for DHCP dynamic address allocation?

DHCPDISCOVER Explanation: When a computer boots for the first time with the DHCP client active, the client generates a series of DHCPDISCOVER messages to solicit an IP address assignment from a DHCP server and broadcasts them on the local network.

What is the first packet sent to a DHCP server when a computer boots up?

c. This prevents accidental duplication of permanently assigned IP addresses. Explanation: Manual allocation means the DHCP server permanently assigns a specific IP address to a specific computer on the network. Although you can just as easily configure such computers manually, DHCP reservations prevent the accidental duplication of permanently assigned IP addresses.

What is the key benefit of DHCP manual IP address allocation over manually configuring the IP address by person? 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 prevents accidental duplication of permanently assigned IP addresses. d. This manually assigned address is officially known as a reservation.

c. Domain controllers, Internet web servers, and DHCP servers Explanation: Although DHCP is an excellent TCP/IP configuration solution for most computers on a network, it is not a good solution for a few components. Domain controllers, Internet web servers, and DHCP servers themselves need static IP addresses.

What kinds of servers should NOT be DHCP clients? a. Servers on a subnet outside the broadcast domain of the DHCP server b. DHCP servers c. Domain controllers, Internet web servers, and DHCP servers d. DHCP relay agents

The client Explanation: The client always initiates DHCP communication.

What machine always initiates the communication between DHCP server and the client in lease negotiation?

a. Web servers, DHCP servers, and domain controllers

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

Configures the IP address and other TCP/IP settings on network computers Explanation: The Dynamic Host Configuration Protocol (DHCP) service automatically configures the Internet Protocol (IP) address and other TCP/IP settings on network computers by assigning addresses from a pool (called a scope) and reclaiming them when they are no longer in use.

What service does Dynamic Host Configuration Protocol (DHCP) provide?

When installing the DHCP role on a computer that is a member of an AD DS domain Explanation: When you install the DHCP Server role on a computer that is a member of an Active Directory Domain Services (AD DS) domain, the DHCP Server is automatically authorized to allocate IP addresses to clients that are also members of the same domain. If the server is not a domain member when you install the role, and you join it to a domain later, you must manually authorize the DHCP server in the domain.

When is it necessary to select Authorize a DHCP server in Active Directory?

Add-DhcpServerv4Scope Explanation: To add an IPv4 scope to a DHCP server using Windows PowerShell, you use the Add-DhcpServerv4Scope cmdlet with the following basic syntax: Add-DhcpServerv4Scope -Name <name> -StartRange <address> -EndRange <address> -SubnetMask <mask> -State Active|Inactive.

Which Windows PowerShell cmdlets creates an IPv4 DHCP scope?

c. DHCPDISCOVER

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

d. DHCPINFORM

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

b. routers d. Windows Server 2012 R2 computers

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 R2 computers

Remote Access Explanation: Many routers can function as DHCP relay agents, but in situations where they cannot, you can configure a Windows Server 2012 computer to function as a relay agent by installing the Remote Access Role.

Which of the following roles must be installed in order to deploy a DHCP Relay Agent on Windows Server 2012 R2?

Create a reservation in the DHCP scope. Explanation: In a Windows DHCP server, a manually allocated address is called a reservation. You create a reservation by expanding the scope node, right-clicking the Reservations node, and, from the context menu, selecting New Reservation.

Which of the following steps must be completed in order to do ensure a network printer is assigned the same address through the DHCP server?

c. manual allocation

Which of the following types of DHCP address allocation is the equivalent of a reservation in Windows Server 2012 R2? a. dynamic allocation b. automatic allocation c. manual allocation d. hybrid allocation

a. Install Windows 8.1 using Pre-boot Execution Environment (PXE) and Windows Deployment Services (WDS).

You are preparing to deploy Windows 8.1 to a large number of new workstations. Which of the following options would be best? a. Install Windows 8.1 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.

b. Deploy additional DHCP servers on the most burdened subnets. Explanation: Because each DHCP server has to support only the local subnet, the impact of the role on each server's disk subsystem and network traffic burden is significant, but relatively light. If your network design already calls for at least one server on every subnet, adding the DHCP Server role to each subnet can be an acceptable solution.

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 option 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.