 IPAddress is the IP address for the lease you want to remove, such as 192.168.1.8. To activate or deactivate a scope, type the following: netsh dhcp server ServerID scope NetworkID state StateVal where the following is true:  ServerID is the UNC name or IP address of the DHCP server on which you want to create the scope, such as \\CORPSVR03 or \\192.168.1.1.  NetworkID is the network ID of the scope, such as 192.168.1.0.  StateVal is set to 0 to deactivate the scope and 1 to activate it. If you are using a switched network where multiple logical networks are hosted on a single physical network, use 2 to deactivate the scope and 3 to activate the scope. Confi guring TCP/IP Options The messages clients and servers broadcast to each other allow you to set TCP/IP options that clients can obtain by default when they obtain a lease or can request if they need additional information. It is important to note, however, that the types of informa- tion you can add to DHCP messages is limited in several ways:  DHCP messages are transmitted using User Datagram Protocol (UDP), and the entire DHCP message must fi t into the UDP datagram. On Ethernet with 1500- byte datagrams, this leaves 1236 bytes for the body of the message (which con- tains the TCP/IP options).  BOOTP messages have a fi xed size of 300 bytes as set by the original BOOTP standard. Any clients using BOOTP are likely to have their TCP/IP options truncated.  Although there are many options that you can set, clients understand only certain TCP/IP options. Thus, the set of options available to you is dependent upon the client’s implementation of DHCP. With that in mind, let’s look at the levels at which options can be assigned and the options that Windows clients understand. Levels of Options and Their Uses Each individual TCP/IP option such as a default gateway is confi gured separately. There are different scope options for IPv4 and IPv6. DHCP administrators can manage options at fi ve levels within the DHCP server confi guration:  Predefi ned options Allow DHCP administrators to specify the way in which options are used and to create new option types for use on a server. In the DHCP console, you can view and set predefi ned options by right-clicking the IPv4 or IPv6 node in the console tree and selecting Set Predefi ned Options. Configuring TCP/IP Options 717 Chapter 22 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.  Server options Allow DHCP administrators to confi gure options that are assigned to all scopes created on the DHCP server. Think of server options as global options that would be assigned to all clients. Server options can be over- ridden by scope, class, and client-assigned options. In the DHCP console, you can view and set server options by expanding the entry for the server you want to work with, right-clicking Server Options, and then choosing Confi gure Options.  Scope options Allow DHCP administrators to confi gure options that are assigned to all clients that use a particular scope. Scope options are assigned only to nor- mal scopes and can be overridden by class and client-assigned options. In the DHCP console, you can view and set scope options by expanding the scope you want to work with, right-clicking Scope Options, and then choosing Confi gure Options.  Class options Allow DHCP administrators to confi gure options that are assigned to all clients of a particular class. Client classes can be user-defi ned or vendor- defi ned. Two classes included with the DHCP Server service are Windows 98, which is used to assign specifi c options to clients running Windows 98, and Windows 2000, which is used to assign specifi c options to clients running Windows 2000 or later. Class options can be overridden by client-assigned options. You defi ne new user and vendor classes by right-clicking the IPv4 or IPv6 entry and selecting either Defi ne User Classes or Defi ne Vendor Classes as appropriate. When defi ned, class options can be confi gured on the Advanced tab of the Server Options, Scope Options, and Reservation Options dialog boxes.  Reservation options Allow administrators to set options for an individual client that uses a reservation. Also referred to as client-specifi c options. After you create a reservation for a client, you can confi gure reservation options by expanding the scope, expanding Reservations, right-clicking the reservation, and selecting Con- fi gure Options. Only TCP/IP options manually confi gured on a client can over- ride client-assigned options. Options Used by Windows Clients RFC 3442 defi nes many TCP/IP options that you can set in DHCP messages. Although you can set all of these options on a DHCP server, the set of options available is depen- dent upon the client’s implementation of DHCP. Table 22-1 shows the options that can be confi gured by administrators and used by Windows computers running the DHCP Client service. Each option has an associated option code, which is used to identify it in a DHCP message, and a data entry, which contains the value setting of the option. These options are requested by clients to set their TCP/IP confi guration. Chapter 22 718 Chapter 22 Managing DHCP Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Table 22-1 Standard TCP/IP Options That Administrators Can Confi gure Option Name Option Code Description Router 003 Sets a list of IP addresses for the default gateways that should be used by the client. IP addresses are listed in order of preference. DNS Servers 006 Sets a list of IP addresses for the DNS servers that should be used by the client. IP addresses are listed in order of preference. DNS Domain Name 015 Sets the DNS domain name that clients should use when resolving host names using DNS. WINS/NBNS Servers 044 Sets a list of IP addresses for the WINS servers that should be used by the client. IP addresses are listed in order of preference. WINS/NBT Node Type 046 Sets the method to use when resolving NetBIOS names. The acceptable values are: 0x1 for B-node (broadcast), 0x2 for P-node (peer-to-peer), 0x4 for M-node (mixed), and 0x8 for H-node (hybrid). See “NetBIOS Node Types” on page 824. NetBIOS Scope ID 047 Sets the NetBIOS scope for the client. Using User-Specifi c and Vendor-Specifi c TCP/IP Options DHCP uses classes to determine which options are sent to clients. The user classes let you assign TCP/IP options according to the type of user the client represents on the network. The default user classes include the following:  Default User Class An all-inclusive class that includes clients that don’t fi t into the other user classes, such as computers running Windows NT 4.0. Any computer running a version of the Windows operating system earlier than Windows 2000 is in this class.  Default BOOTP Class Any computer running Windows 2000 or later has this user class if it is connected to the local network directly. This means Windows 2000, Windows XP, and Windows Server 2008 computers connected with a wired net- work interface have this class.  Default Routing And Remote Access Class Any computer that connects to the network using RRAS has this class. Any settings applied to this class are used by dial-in and VPN users, which allows you to set different TCP/IP options for these users.  Default Network Access Protection Class Any computer that connects to the net- work and is subject to Network Access Protection (NAP) policy has this class. Any settings applied to this class are used by restricted access clients, which allows you to set different TCP/IP options for these users. Configuring TCP/IP Options 719 Chapter 22 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Clients can be a member of multiple user classes, and you can view the user class memberships for each network interface by typing ipconfi g /showclassid * at the com- mand prompt. (The asterisk tells the command that you want to see all the network interfaces.) The output you’ll see on a computer running Windows 2000 or later will be similar to the following: Windows IP Confi guration DHCP Classes for Adapter "Local Area Connection": DHCP ClassID Name : Default Routing and Remote Access Class DHCP ClassID Description : User class for remote access clients DHCP ClassID Name : Default BOOTP Class DHCP ClassID Description : User class for BOOTP Clients Here, the client is a member of the Default Routing And Remote Access Class and the Default BOOTP Class. The client doesn’t, however, get its options from both classes. Rather, the class from which the client gets its options depends on its connection state. If the client is connected directly to the network, it uses the Default BOOTP Class. If the client is connected by Routing and Remote Access, it uses the Default Routing And Remote Access Class. Vendor classes work a bit differently because they defi ne the set of options available to and used by the various user classes. The default vendor class, DHCP Standard Options, is used to set the standard TCP/IP options, and the various user classes all have access to these options so that they can be implemented in a user-specifi c way. Additional vendor classes beyond the default defi ne extensions or additional options that can be implemented in a user-specifi c way. This means that the vendor class defi nes the options and makes them available, while the user class settings determine which of these additional options (if any) are used by clients. The default vendor classes that provide additional (add-on) options are as follows:  Microsoft Options Add-on options available to any client running any version of Windows  Microsoft Windows 98 Options Add-on options available to any client running Windows 98 or later  Microsoft Windows 2000 Options Add-on options available to any client running Windows 2000 or later When it comes to these classes, a client applies the options from the most specifi c add- on vendor class. Thus, a Windows 98 client would apply the Microsoft Windows 98 Options vendor class, and a Windows 2000 or later client would apply the Microsoft Windows 2000 Options vendor class. Again, these options are in addition to the stan- dard options provided through the DHCP Standard Options vendor class and can be Chapter 22 720 Chapter 22 Managing DHCP Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. implemented in a manner specifi c to a user class. This means you can have one set of add-on options for directly connected clients (Default BOOTP Class) and one set for remotely connected clients (Default Routing And Remote Access Class). The add-on options that can be set for a client running Windows 2000 or later are listed in Table 22-2. Table 22-2 Additional TCP/IP Options That Administrators Can Confi gure Option Name Option Code Description Microsoft Disable NetBIOS Option 001 Disables NetBIOS if selected as an option with a value of 0x1. Microsoft Release DHCP Lease On Shutdown Option 002 Specifi es that a client should release its DHCP lease on shutdown if selected as an option with a value of 0x1. Microsoft Default Router Metric Base 003 Specifi es that the default router metric base should be used if selected as an option with a value of 0x1. Settings Options for All Clients On the DHCP server, you can set TCP/IP options at several levels. You can set options for the following components:  All scopes on a server In the DHCP console, expand the entry for the server and IP protocol you want to work with, right-click Server Options, and then choose Confi gure Options.  A specifi c scope In the DHCP console, expand the scope you want to work with, right-click Scope Options, and then choose Confi gure Options.  A single reserved IP address In the DHCP console, expand the scope, expand Reservations, right-click the reservation you want to work with, and select Confi g- ure Options. Regardless of the level at which you are setting TCP/IP options, the dialog box dis- played has the exact same set of choices as that shown in Figure 22-21. You can now select each standard TCP/IP option you want to use in turn, such as Router, DNS Serv- ers, DNS Domain Name, WINS/NBNS Servers, and WINS/NBT Node Type, and confi g- ure the appropriate values. Click OK when you are fi nished. Configuring TCP/IP Options 721 Chapter 22 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Figure 22-21 Set class-specific options using the General tab. Settings Options for RRAS and NAP Clients On the DHCP server, you can set TCP/IP options for RRAS and NAP clients at several levels. You can set options for the following components:  All scopes on a server In the DHCP console, expand the entry for the server and IP protocol you want to work with, right-click Server Options, and then choose Confi gure Options.  A specifi c scope In the DHCP console, expand the scope you want to work with, right-click Scope Options, and then choose Confi gure Options.  A single reserved IP address In the DHCP console, expand the scope, expand Reservations, right-click the reservation you want to work with, and select Confi g- ure Options. Regardless of the level at which you are setting TCP/IP options, the dialog box dis- played has the exact same set of choices. You can now complete the following steps: 1. Click the Advanced tab, as shown in Figure 22-22. From the Vendor Class drop- down list, select DHCP Standard Options. As appropriate, from the User Class drop-down list, choose either Default Routing And Remote Access Class or Default Network Access Protection Class. Chapter 22 722 Chapter 22 Managing DHCP Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Figure 22-22 Set the DHCP Standard Options. 2. Select the check box for each standard TCP/IP option you want to use in turn, such as Router, DNS Servers, DNS Domain Name, WINS/NBNS Servers, and WINS/NBT Node Type, and confi gure the appropriate values. 3. Select each add-on TCP/IP option you want to use in turn, such as Microsoft Disable NetBIOS Option and Microsoft Release DHCP Lease On Shutdown Option, and accept the default value (0x1) to turn on the option. 4. Click OK. Setting Add-On Options for Directly Connected Clients You can set add-on options for directly connected clients that are different from those of remote access clients. Access the TCP/IP Options dialog box at the appropriate level, and then click the Advanced tab. For Windows 2000 or later clients, select Microsoft Windows 2000 Options as the vendor class and Default BOOTP Class as the user class, as shown in Figure 22-23. Now select each add-on TCP/IP option you want to use in turn, such as Microsoft Disable NetBIOS Option and Microsoft Release DHCP Lease On Shutdown Option, and accept the default value (0x1) to turn on the option. Then click OK when you are fi nished. Configuring TCP/IP Options 723 Chapter 22 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Figure 22-23 Set the add-on options for directly connected clients. Defi ning Classes to Get Different Option Sets If you want a group of DHCP clients to use a set of options different than other comput- ers, you can use classes to do this. It is a two-part process. First, create your own user- defi ned class on each DHCP server to which the clients might connect. Then confi gure the network interfaces on the clients to use the new class. Creating the Class In the DHCP console, you can defi ne the new user class by right-clicking the IP protocol you want to work with and selecting Defi ne User Classes. In the DHCP User Classes dialog box, shown in Figure 22-24, the existing classes are listed, except for the Default User Class because it is the base user class. Click Add to display the New Class dialog box shown in Figure 22-25. In the Display Name box, type the name of the class you are defi ning. The name is arbitrary and should be short but descriptive enough so that you know what that class is used for by seeing its name. You can also type a description in the Description box. Afterward, click in the empty area below the word ASCII. In this space, type the class identifi er, which is used by DHCP to identify the class. The class identifi er cannot have spaces. Click OK to close the New Class dialog box, and then click Close to return to the DHCP console. Chapter 22 724 Chapter 22 Managing DHCP Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Figure 22-24 User classes in addition to the base class. Figure 22-25 Set the class name, description, and class ID. Next, you must confi gure the TCP/IP options that should be used by this class. In the DHCP console, expand the entry for the server you want to work with, right-click Server Options, and then choose Confi gure Options. In the Server Options dialog box, click the Advanced tab. Select DHCP Standard Options as the vendor class and the class you created as the user class. Select each standard TCP/IP option you want to use in turn, such as Router, DNS Servers, DNS Domain Name, WINS/NBNS Servers, and WINS/NBT Node Type, and confi gure the appropriate values. If you want to set Windows options, select Microsoft Windows 2000 Options as the vendor class. Don’t change the user class. Then select each add-on TCP/IP option you want to use in turn, such as Microsoft Disable Net- BIOS Option and Microsoft Release DHCP Lease On Shutdown Option, and accept the default value (0x1) to turn on the option. Click OK to complete the confi guration of the new class. Configuring TCP/IP Options 725 Chapter 22 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Confi guring Clients to Use the Class Now you must confi gure the network interfaces on the clients to use the new class. Assuming “Local Area Connection” is the name of the network interface on the client, you would type the following command to do this: ipconfi g /setclassid "Local Area Connection" ClassID where ClassID is the ID of the user class to use. For example, if the class ID is Engineer- ing, you would type ipconfi g /setclassid "Local Area Connection" Engineering In these examples, I use “Local Area Connection” as the network interface name because that is the default connection created by Windows. If a client has multiple net- work interfaces or a user has changed the name of the default network interface, you must use the name of the appropriate interface. You can get a list of all network inter- faces on a client by typing ipconfi g /all at the command prompt. After you set the class ID, type ipconfi g /renew at the command prompt. This tells the client to renew the lease and because the client has a new class ID it also forces the cli- ent to request new TCP/IP options. The output should be similar to the following: Windows IP Confi guration Ethernet adapter Local Area Connection: Connection-specifi c DNS Suffi x : IP Address : 192.168.1.22 Subnet Mask : 255.255.255.0 Default Gateway : 192.168.1.1 DHCP Class ID : Engineering That’s it. Because the class ID is persistent, you need to set it only once. So, if the client is restarted, the class ID will remain. To remove the class ID and use the defaults again, type the following command: ipconfi g /setclassid "Local Area Connection" TROUBLESHOOTING Class ID problems Sometimes the network interface won’t report that it has the new class ID. If this hap- pens, try releasing the DHCP lease fi rst by typing ipconfi g /release and then obtaining a new lease by typing ipconfi g /renew. TROUBLESHOOTING Chapter 22 726 Chapter 22 Managing DHCP Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. [...]... to a new server For example, before upgrading a DHCP server or decommissioning it, you could configure a new DHCP server and move the current DHCP database from the old server to the new server Start by installing the DHCP Server service on the destination server and then restart the server When the server restarts, log on, and at the command prompt type net stop "dhcp server" to stop the DHCP Server. .. Chapter 22 netsh dhcp server ServerID set detectconflictretry Attempts where ServerID is the name or IP address of the DHCP server and Attempts is the number of conflict detection attempts the server should use You can confirm the setting by typing the following: netsh dhcp server ServerID show detectconflictretry Saving and Restoring the DHCP Configuration After you finish configuring a DHCP server, you should... Maintenance 729 location Click OK If you change the audit log location, Windows Server 2008 will need to restart the DHCP Server service When prompted to confirm that this is OK, click Yes Binding the DHCP Server Service to a Network Interface The DHCP Server service should bind automatically to the fi rst NIC on the server This means that the DHCP Server service should use the IP address and TCP/IP configuration... been implemented on many operating systems including UNIX and Microsoft Windows All versions of Windows automatically install a DNS client as part of Transmission Control Protocol/Internet Protocol (TCP/IP) To get the server component, you must install the DNS Server service All editions of Windows Server 2008 include the DNS Server service Because DNS is the name resolution service for Active Directory,... dhcp server ServerID set databasepath NewPath—Sets the new path for the database files, such as C:\Dhcp\Dbfiles Chapter 22 Netsh dhcp server ServerID set databasebackupinterval NewIntervalMinutes— Sets the database backup interval in minutes, such as 120 Netsh dhcp server ServerID set databasebackuppathname NewPath—Sets the new path for the database backup fi les, such as C:\Dhcp\Dbbackup Netsh dhcp server. .. All Scopes to enable or disable NAP for all scopes on the server Note When the local DHCP server is also a Network Policy Server, the Network Policy Server should always be reachable If you haven’t configured the server as a Network Policy Server or the DHCP server is unable to contact the designated Network Policy Server, you’ll see an error stating this on the Network Access Protection tab Please purchase... easily restore the server to a known state or use the same settings on another server To do this, type the following command at the command prompt: netsh dhcp server dump ServerID > SaveFile where ServerID is the name or IP address of the DHCP server and SaveFile is the name of the file in which you want to store the configuration settings When you are logged on locally, you can omit the server name or IP... for the www.cpandl.com server, the DNS client on your computer queries the local name server as specified in its TCP/IP configuration The local name server forwards the request to the root server for the external resource domain This domain contacts the name server for the related top-level domain, which in turn contacts the name server for the cpandl.com domain This authoritative server sends a response,... domain tree Although many types of resource records are defined and supported by DNS servers, only a few record types are actually used on a Windows Server 2008 network So, with that in mind, Table 23-2 provides an overview of the resource records that you’ll use Table 23-2 Common Resource Records Used on Windows Server 2008 Networks Chapter 23 Record Type Common Name A Host address Contains the name... single DNS server, called a primary DNS server This server s SOA record indicates that it is the primary zone for the related domain Secondary zones are used to improve performance and provide redundancy A server storing a copy of a secondary zone is referred to as a secondary DNS server A primary DNS server automatically replicates a copy of the primary zone to any designated secondary servers The . running Windows 2000 or later has this user class if it is connected to the local network directly. This means Windows 2000, Windows XP, and Windows Server 2008. prompt: netsh dhcp server ServerID show dbproperties where ServerID is the name or IP address of the DHCP server, such as netsh dhcp server 192.168.1.50