MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration Chapter 4 Installing and Configuring the Dynamic Host Configuration Protocol

MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration 2 Objectives Discuss the basics of Dynamic Host Configuration Protocol (DHCP) Describe the components and processes of DHCP Install DHCP in a Windows Server 2008 environment Configure the DHCP server Administer DHCP on clients and servers Troubleshoot DHCP

3 Basics of DHCP DHCP –Layer 4 protocol that uses User Datagram Protocol (UDP) datagrams for communication –Defined by Request for Comment (RFC) 2131 –Clients use UDP port 68 to send and receive DHCP broadcast communication –Servers use UDP port 67 to send and receive DHCP broadcast communication MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

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5 Exploring DHCP Components and Processes DHCP lease –Defines the amount of time, or the duration, that an IP address is loaned to a DHCP client Lease duration –Amount of time a client keeps an IP address before releasing it DHCP scope –A range of IP addresses and related configuration information available by request from a DHCP client MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

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7 Exploring DHCP Components and Processes (continued) DHCP options –IP address –Subnet mask –Default gateway –Primary and secondary DNS servers –DHCP lease expiration DHCP reservations –Allow you to assign a specific IP address to a DHCP client without statically configuring the device with IP information MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

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10 DHCP Communication Processes DHCP message types –DHCPDiscover, DHCPOffer –DHCPRequest, DHCPAck –DHCPNack, DHCPDecline Initial lease request –Clients make these requests if they do not have a current lease on a scope Lease renewals –Intervals: Renewal time value and Binding time value MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

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12 DHCP Communication Processes (continued) Changing subnets –When a client moves to a new subnet, it cannot use its current lease because the IP information does match the new network configuration MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

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14 Using DHCPv6 IPv6 clients –Use DHCP to receive IP address and configuration information from an IPv6 router on their network Implementing DHCPv6 requires –Configuring your router to forward all autoconfiguration requests to an available DHCPv6 server –Disabling stateless mode on your Windows Server 2008 DHCP servers MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Installing DHCP in a Windows Server 2008 Environment DHCP Server role –Requires minimal server resources –Starts the DHCP Server service –Installs the files needed for the DHCP database –Initializes the DHCP console on the local system 15 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

16 Installing DHCP in a Windows Server 2008 Environment (continued) Activity 4-1: Installing the DHCP Server Role Time Required: 15 minutes Objective: Install the DHCP server role MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

17 Installing DHCP in a Windows Server 2008 Environment (continued) DHCP database –Based on the Joint Engine Technology (JET) storage engine –Database size is based on the number of client requests it receives DHCP Server service –Installed with the DHCP Server role DHCP Server console –The GUI tool for managing DHCP on Windows Server 2008 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

18 Installing DHCP in a Windows Server 2008 Environment (continued) Activity 4-2: Reviewing the DHCP Server Console Time Required: 5 minutes Objective: Explore the DHCP Server console MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

19 Authorizing DHCP In Active Directory domains –DHCP servers must be authorized before they can begin supplying IP addresses In Windows Server 2008 –You are prompted for credentials during installation if your server is a member of a domain MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

20 Configuring the DHCP Server After installing the DHCP role –You need to configure DHCP for its initial use DHCP –Requires at least one DHCP scope to issue IP addresses for network clients MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Activity 4-3: Creating a Scope for the Subnet Time Required: 10 minutes Objective: Create scopes in the DHCP console 21 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration Configuring the DHCP Server (continued)

22 Configuring the DHCP Server (continued) Activity 4-4: Creating a Scope for an IPv6 Subnet Time Required: 10 minutes Objective: Create an IPv6 scope in the DHCP console MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

23 Activity 4-5: Activating an IPv4 DHCP Scope Time Required: 5 minutes Objective: Activate a DHCP scope MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration Configuring the DHCP Server (continued)

24 Configuring the DHCP Server (continued) Activity 4-6: Expanding an IPv4 Address Pool Time Required: 5 minutes Objective: Modify an IPv4 address pool MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

25 Configuring Exclusions Exclusions are created so that: –Static IP addresses for devices such as routers, printers, or other network devices are not assigned Common practice –Create exclusionary ranges at the beginning and end of a scope range MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

26 Configuring Exclusions (continued) Activity 4-7: Adding IPv4 Exclusion Time Required: 10 minutes Objective: Create IPv4 exclusionary ranges MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

27 Configuring Options Options –Allow you to quickly and easily provide DHCP clients with updated configuration information If you are using the default lease duration of eight days –Could take up to four days before clients receive the new DHCP options you deploy MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

28 Configuring Options (continued) Activity 4-8: Modifying the Server Options Time Required: 10 minutes Objective: Modify the DHCP server options MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Configuring Options (continued) Activity 4-9: Modifying the Scope Options Time Required: 10 minutes Objective: Modify the DHCP scope options 29 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

30 Creating Reservations Reservations –Used in DHCP to give a DHCP client a static IP address without manually configuring the address on the client MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

31 Creating Reservations (continued) Activity 4-10: Adding a Reservation for Time Required: 5 minutes Objective: Add a reservation for a new network printer MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

32 Using netsh Syntax for creating a DHCP reservation netsh Dhcp Server Scope add reservedip c40fb6a MSN-SRV-150 Syntax for creating a DHCP exclusionary range netsh Dhcp Server Scope add excluderange MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

33 DHCP Client Configuration DHCP Client service –Responsible for the DHCP configuration process on a client machine Fault tolerance and DHCP –Microsoft recommends using an 80/20 rule for splitting scopes between two servers for fault tolerance –80/20 rule 80 percent of a scope’s total IP range is hosted on your primary DHCP server, while the remaining 20 percent is hosted on your secondary DHCP server MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

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35 DHCP Administration Monitoring reliability and performance –Monitoring allows you to determine the current state of DHCP –Reliability and Performance Monitor Used to create a real-time picture of what is happening on the local or remote server MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Monitoring Reliability and Performance Activity 4-11: Adding Counters to Performance Monitor Time Required: 10 minutes Objective: Configure Performance Monitor by adding DHCP Server counters 36 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

37 DHCP console statistics –Server statistics: broader and provide a more comprehensive picture of the status of your DHCP server –Scope statistics: display information about each scope MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration Monitoring Reliability and Performance (continued)

Activity 4-12: Viewing Statistics Time Required: 5 minutes Objective: View server and scope statistics 38 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Monitoring Reliability and Performance (continued) DHCP audit log –Lists detailed information about events occurring on a specific day, including Event ID, Date and time Event description, IP address Host name, MAC address 39 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Monitoring Reliability and Performance (continued) Activity 4-13: Viewing Audit Logs Time Required: 10 minutes Objective: View audit logs 40 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Backup and Recovery Automatic backup –Windows Server 2008 performs an automated backup of the DHCP database every 60 minutes Manual backup –Stored in the %systemroot%\systemroot\dhcp\backup folder Restoring the DHCP database from a backup –You can restore a DHCP database from an offline backup when you are building a new DHCP server 41 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Backup and Recovery (continued) Activity 4-14: Performing a Manual Backup Time Required: 10 minutes Objective: Back up the DHCP database 42 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Backup and Recovery (continued) Activity 4-15: Restoring a DHCP Database Time Required: 10 minutes Objective: Restoring the DHCP database 43 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Troubleshooting DHCP Reconciling the database –Validates the DHCP database by comparing it with the Registry values of the operating system to verify that the database contains the most current data 44 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Troubleshooting DHCP (continued) Activity 4-16: Reconciling the DHCP Database Time Required: 10 minutes Objective: Reconcile individual and all scopes in the DHCP console 45 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Verifying DHCP Services To determine the running services on a system –Enter the net start command at a command prompt To stop a running service net stop “DHCP Server” or “DHCP Client” net start “DHCP Server” or “DHCP Client” 46 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Troubleshooting DHCP Clients: IPconfig ipconfig –Can be used to renew the current IP address and configuration information and to release the current IP address Entering the ipconfig /release command –Issues the DHCPRelease message to the server currently holding the IP address lease for a client 47 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

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50 Summary Information provided by a DHCP server includes: –Leases, scopes, and options For DHCP to function properly in a routed network: –A DHCP relay agent or an RFC 1542–compliant router needs to be in place to pass along DHCP messages DHCP –Uses a standard set of messages for communicating between DHCP clients and DHCP servers MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

51 Summary (continued) Common communication processes –Initial lease requests, lease renewals, and changing subnet renewals All data in DHCP is stored in the DHCP database Only DHCP servers in an Active Directory domain need to be authorized After DHCP is installed –You must configure scopes for DHCP clients to receive addresses MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration

Summary (continued) DHCP console or netsh –Can be used to perform all configuration tasks DHCP –Uses exclusions to prevent making the IP addresses of statically assigned devices available in an IP scope range To monitor DHCP –Use Performance Monitor, DHCP statistics, and the DHCP audit log 52 MCTS Guide to Microsoft Windows Server 2008 Network Infrastructure Configuration