nasser naif windows server 2012 dhcb

INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION

Dynamic Host Configuration Protocol (DHCP) Dynamic Host Configuration Protocol (DHCP) Dynamic Host Configuration Protocol (DHCP) Dynamic Host Configuration Protocol (DHCP)

• Designed in 1993• An extension of BOOTP (Many similarities to BOOTP)• Same port numbers as BOOTP • Extensions:• Extensions:oSupports temporary allocation (“leases”) of IP addressesoDHCP client can acquire all IP configuration parameters

• DHCP is the preferred mechanism for dynamic assignment of IP addresses

• DHCP can interoperate with BOOTP clients.

UNDERSTANDING DHCP

The Dynamic Host Configuration Protocol (DHCP)Dynamic Host Configuration Protocol (DHCP)Dynamic Host Configuration Protocol (DHCP)Dynamic Host Configuration Protocol (DHCP)service:

� Automatically configures the IP address and other TCP/IP settings on network computers by Automatically configures the IP address and other TCP/IP settings on network computers by assigning addresses from a pool (called a scopescopescopescope) and reclaiming them when they are no longer in use.

� Saves time.

� Prevents configuration errors.

THE CONSIST OF DHCP

DHCP consists of three components:

� DHCP server applicationDHCP server applicationDHCP server applicationDHCP server application: Responds to client requests

for TCP/IP configuration settings.

� DHCP clientDHCP clientDHCP clientDHCP client: Issues requests to servers and applies � DHCP clientDHCP clientDHCP clientDHCP client: Issues requests to servers and applies

the TCP/IP configuration settings it receives to the

local computer.

� DHCP communications protocolDHCP communications protocolDHCP communications protocolDHCP communications protocol: Defines the formats

and sequences of the messages exchanged by DHCP

clients and servers.

THE DIFFERENT IP ADDRESS ALLOCATION METHODS

�Dynamic allocation:Dynamic allocation:Dynamic allocation:Dynamic allocation: The DHCP server assigns an IP address to a client computer from a scope, for a specified length of time. DHCP servers only lease addresses to clients with this method.

�Automatic allocation:Automatic allocation:Automatic allocation:Automatic allocation: The DHCP server permanently assigns an IP address to a client computer from a scope.

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

�Manual allocation:Manual allocation:Manual allocation:Manual allocation: The DHCP server permanently assigns a specific IP address to a specific computer on the network. It is called a reservation. You use manually allocated addresses for computers that must have the same IP address at all times.

DHCP OPTIONSThere are many other TCP/IP parameters that can

be configured by DHCP besides the IP address:

oMagic cookieoOption formatooDHCP Message Type optionoPad optionoOption Overload optionoVendor-Specific Information optionoEnd option

DHCP INTERACTION (SIMPLIFIED)DHCP INTERACTION (SIMPLIFIED)DHCP INTERACTION (SIMPLIFIED)DHCP INTERACTION (SIMPLIFIED)

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)١ (UNDERSTANDING DHCP FAILOVERUNDERSTANDING DHCP FAILOVERUNDERSTANDING DHCP FAILOVERUNDERSTANDING DHCP FAILOVER

� DHCP failover involves configuring two Server DHCP failover involves configuring two Server DHCP failover involves configuring two Server DHCP failover involves configuring two Server 2012201220122012 computers with the DHCP role service installed computers with the DHCP role service installed computers with the DHCP role service installed computers with the DHCP role service installed

as a pair. This pair can provide a highly available DNS using one of the following techniques:as a pair. This pair can provide a highly available DNS using one of the following techniques:as a pair. This pair can provide a highly available DNS using one of the following techniques:as a pair. This pair can provide a highly available DNS using one of the following techniques:

� Load balance mode.Load balance mode.Load balance mode.Load balance mode. The load balance mode (sometimes referred to as the load sharing mode in the The load balance mode (sometimes referred to as the load sharing mode in the The load balance mode (sometimes referred to as the load sharing mode in the The load balance mode (sometimes referred to as the load sharing mode in the

Microsoft documentation) is the default way of configuring DHCP failover. When you configure two Microsoft documentation) is the default way of configuring DHCP failover. When you configure two Microsoft documentation) is the default way of configuring DHCP failover. When you configure two Microsoft documentation) is the default way of configuring DHCP failover. When you configure two

DHCP servers in load balance mode, each server will serve IP addresses from the same scope in DHCP servers in load balance mode, each server will serve IP addresses from the same scope in DHCP servers in load balance mode, each server will serve IP addresses from the same scope in DHCP servers in load balance mode, each server will serve IP addresses from the same scope in

such a way that duplicate addresses aren't issued. Address leases from the scope are issued by such a way that duplicate addresses aren't issued. Address leases from the scope are issued by such a way that duplicate addresses aren't issued. Address leases from the scope are issued by such a way that duplicate addresses aren't issued. Address leases from the scope are issued by

each server in a load balanced manner. If one DHCP server fails, the other will continue to lease each server in a load balanced manner. If one DHCP server fails, the other will continue to lease each server in a load balanced manner. If one DHCP server fails, the other will continue to lease each server in a load balanced manner. If one DHCP server fails, the other will continue to lease

addresses until the first DHCP server returns to service. Figure addresses until the first DHCP server returns to service. Figure addresses until the first DHCP server returns to service. Figure addresses until the first DHCP server returns to service. Figure 1111 shows a DHCP scope configured to shows a DHCP scope configured to shows a DHCP scope configured to shows a DHCP scope configured to

use the load balance mode.use the load balance mode.use the load balance mode.use the load balance mode.

Hot standby mode.Hot standby mode.Hot standby mode.Hot standby mode.When you configure two servers with the DHCP role installed When you configure two servers with the DHCP role installed When you configure two servers with the DHCP role installed When you configure two servers with the DHCP role installed

in hot standby mode, the servers operate in a failover relationship. The active in hot standby mode, the servers operate in a failover relationship. The active in hot standby mode, the servers operate in a failover relationship. The active in hot standby mode, the servers operate in a failover relationship. The active

server leases IP addresses and configuration information to clients. The server leases IP addresses and configuration information to clients. The server leases IP addresses and configuration information to clients. The server leases IP addresses and configuration information to clients. The

secondary server only performs this function in the event that the primary isn't secondary server only performs this function in the event that the primary isn't secondary server only performs this function in the event that the primary isn't secondary server only performs this function in the event that the primary isn't

available. Figure available. Figure available. Figure available. Figure 2222 shows a DHCP scope configured to use the hot standby shows a DHCP scope configured to use the hot standby shows a DHCP scope configured to use the hot standby shows a DHCP scope configured to use the hot standby

mode.mode.mode.mode.

CONFIGURING DHCP FAILOVER (CONFIGURING DHCP FAILOVER (CONFIGURING DHCP FAILOVER (CONFIGURING DHCP FAILOVER (1111))))

DHCP failover involves setting up a partnership between two DHCP DHCP failover involves setting up a partnership between two DHCP DHCP failover involves setting up a partnership between two DHCP DHCP failover involves setting up a partnership between two DHCP

servers. Only two DHCP servers can participate in a partnership, but servers. Only two DHCP servers can participate in a partnership, but servers. Only two DHCP servers can participate in a partnership, but servers. Only two DHCP servers can participate in a partnership, but

you can configure multiple partnerships between DHCP servers. For you can configure multiple partnerships between DHCP servers. For you can configure multiple partnerships between DHCP servers. For you can configure multiple partnerships between DHCP servers. For

example, you can configure DHCPexample, you can configure DHCPexample, you can configure DHCPexample, you can configure DHCP----ONE and DHCPONE and DHCPONE and DHCPONE and DHCP----TWO as partners, TWO as partners, TWO as partners, TWO as partners,

DHCPDHCPDHCPDHCP----TWO and DHCPTWO and DHCPTWO and DHCPTWO and DHCP----THREE as partners, and DHCPTHREE as partners, and DHCPTHREE as partners, and DHCPTHREE as partners, and DHCP----ONE and DHCPONE and DHCPONE and DHCPONE and DHCP----DHCPDHCPDHCPDHCP----TWO and DHCPTWO and DHCPTWO and DHCPTWO and DHCP----THREE as partners, and DHCPTHREE as partners, and DHCPTHREE as partners, and DHCPTHREE as partners, and DHCP----ONE and DHCPONE and DHCPONE and DHCPONE and DHCP----

THREE as partners. An individual DHCP scope, however, can only be THREE as partners. An individual DHCP scope, however, can only be THREE as partners. An individual DHCP scope, however, can only be THREE as partners. An individual DHCP scope, however, can only be

used with one partnership. For example, you can configure SCOPEused with one partnership. For example, you can configure SCOPEused with one partnership. For example, you can configure SCOPEused with one partnership. For example, you can configure SCOPE----

ALPHA as highly available on servers DHCPALPHA as highly available on servers DHCPALPHA as highly available on servers DHCPALPHA as highly available on servers DHCP----ONE and DHCPONE and DHCPONE and DHCPONE and DHCP----TWO, but TWO, but TWO, but TWO, but

this scope can't also be present on DHCPthis scope can't also be present on DHCPthis scope can't also be present on DHCPthis scope can't also be present on DHCP----THREE.THREE.THREE.THREE.


� To configure DHCP failover, perform the following steps:To configure DHCP failover, perform the following steps:To configure DHCP failover, perform the following steps:To configure DHCP failover, perform the following steps:

� Install the DHCP role on two separate servers running Server Install the DHCP role on two separate servers running Server Install the DHCP role on two separate servers running Server Install the DHCP role on two separate servers running Server 2012201220122012 that are members of the same Active that are members of the same Active that are members of the same Active that are members of the same Active

Directory (AD) domain.Directory (AD) domain.Directory (AD) domain.Directory (AD) domain.

� Ensure that the DHCP role on each server is authorized in AD.Ensure that the DHCP role on each server is authorized in AD.Ensure that the DHCP role on each server is authorized in AD.Ensure that the DHCP role on each server is authorized in AD.

� Create the relevant scopes on the first DHCP server.Create the relevant scopes on the first DHCP server.Create the relevant scopes on the first DHCP server.Create the relevant scopes on the first DHCP server.

� Click the scope for which you want to configure failover. On the Action menu, click Configure Failover.Click the scope for which you want to configure failover. On the Action menu, click Configure Failover.Click the scope for which you want to configure failover. On the Action menu, click Configure Failover.Click the scope for which you want to configure failover. On the Action menu, click Configure Failover.

� On theOn theOn theOn the Introduction to DHCP FailoverIntroduction to DHCP FailoverIntroduction to DHCP FailoverIntroduction to DHCP Failover page of the Configure Failover wizard, verify that the scope you selected is page of the Configure Failover wizard, verify that the scope you selected is page of the Configure Failover wizard, verify that the scope you selected is page of the Configure Failover wizard, verify that the scope you selected is � On theOn theOn theOn the Introduction to DHCP FailoverIntroduction to DHCP FailoverIntroduction to DHCP FailoverIntroduction to DHCP Failover page of the Configure Failover wizard, verify that the scope you selected is page of the Configure Failover wizard, verify that the scope you selected is page of the Configure Failover wizard, verify that the scope you selected is page of the Configure Failover wizard, verify that the scope you selected is

present and click Next.present and click Next.present and click Next.present and click Next.

� On theOn theOn theOn the Specify the partner server to use for failoverSpecify the partner server to use for failoverSpecify the partner server to use for failoverSpecify the partner server to use for failover page, click Add Server. As Figure page, click Add Server. As Figure page, click Add Server. As Figure page, click Add Server. As Figure 3333 shows, the Add Server shows, the Add Server shows, the Add Server shows, the Add Server

dialog box will list all the Server dialog box will list all the Server dialog box will list all the Server dialog box will list all the Server 2012201220122012 computers running the DHCP role service that have been authorized in the computers running the DHCP role service that have been authorized in the computers running the DHCP role service that have been authorized in the computers running the DHCP role service that have been authorized in the

domain. Select the DHCP server you want to use as the partner and click OK.domain. Select the DHCP server you want to use as the partner and click OK.domain. Select the DHCP server you want to use as the partner and click OK.domain. Select the DHCP server you want to use as the partner and click OK.

CREATE A HIGHLY AVAILABLE DHCP SOLUTION CREATE A HIGHLY AVAILABLE DHCP SOLUTION CREATE A HIGHLY AVAILABLE DHCP SOLUTION CREATE A HIGHLY AVAILABLE DHCP SOLUTION

WITH MINIMAL WORKWITH MINIMAL WORKWITH MINIMAL WORKWITH MINIMAL WORK

DHCPDHCPDHCPDHCP failoverfailoverfailoverfailover inininin ServerServerServerServer 2012201220122012 providesprovidesprovidesprovides aaaa highlyhighlyhighlyhighly

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scopescopescopescope highlyhighlyhighlyhighly availableavailableavailableavailable onononon aaaa singlesinglesinglesingle relationshiprelationshiprelationshiprelationship....

nasser naif windows server 2012 dhcb

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