IPv6 Server Properties- Configuring DHCP and IPAM

The IPv6 Properties dialog box for the server has two tabs: General and Advanced. On the General tab, you can configure the following settings:

     Frequency with which statistics are updated

■     DHCP auditing

The Advanced tab allows you to configure the following settings:

         Database path for the audit log file path.

         Connection bindings.

       Registration credentials for Dynamic DNS. The registration credential is the user account that DHCP will use to register clients with Active Directory.

Managing Reservations and Exclusions

After defining the address pool for your scope, the next step is to create reservations and exclusions, which reduce the size of the pool. In the following sections, you will learn how to add and remove exclusions and reservations.

Adding and Removing Exclusions

When you want to exclude an entire range of IP addresses, you need to add that range as an exclusion. Ordinarily, you’ll want to do this before you enable a scope because that prevents any of the IP addresses you want excluded from being leased before you have a chance to exclude them. In fact, you can’t create an exclusion that includes a leased address— you have to get rid of the lease first.

Adding an Exclusion Range

Here’s how to add an exclusion range:

  1. Open the DHCP snap- in and find the scope to which you want to add an exclusion (either IPv4 or IPv6).
  2. Expand the scope so that you can see its Address Pool item for IPv4 or the Exclusion section for IPv6.
  3. Right- click the Address Pool or Exclusion section and choose the New Exclusion Range command.
  4. When the Add Exclusion dialog box appears, enter the IP addresses you want to exclude. To exclude a single address, type it in the Start IP Address field. To exclude a range of addresses, also fill in the End IP Address field.
  5. Click the Add button to add the exclusion.

When you add exclusions, they appear in the Address Pool node, which is under the Scope section for IPv4 and under the Exclusion section of IPv6.

Removing an Exclusion Range

To remove an exclusion, just right- click it and choose the Delete command. After confirming your command, the snap- in removes the excluded range and the addresses become immediately available for issuance.

Adding and Removing Reservations

Adding a reservation is simple as long as you have the MAC address of the device for which you want to create a reservation. Because reservations belong to a single scope, you create and remove them within the Reservations node beneath each scope.

Adding a Reservation

To add a reservation, perform the following tasks:

  1. Right- click the scope and select New Reservation.

This displays the New Reservation dialog box, shown in Figure 6.19.

FIGURE 6.19 New Reservation dialog boxes for IPv4 and IPv6

2. Enter the IP address and MAC address or ID for the reservation.

To find the MAC address of the local computer, use the ipconfig command. To find the MAC address of a remote machine, use the nbtstat- acomputername command.

3. If you want, you can also enter a name and description.

4. For IPv4, in the Supported Types section, choose whether the reservation will be made by DHCP only, BOOTP only (useful for remote-a ccess devices), or both.

Removing a Reservation

To remove a reservation, right- click it and select Delete. This removes the reservation but does nothing to the client device.

There’s no way to change a reservation once it has been created. If you want to change any of the associated settings, you’ll have to delete and re- create the reservation.

Setting Scope Options for IPv4

Once you’ve installed a server, authorized it in Active Directory, and fixed up the address pool, the next step is to set scope options that you want sent out to clients, such as router (that is, default gateway) and DNS server addresses. You must configure the options you want sent out before you activate a scope. If you don’t, clients may register in the scope without getting any options, rendering them virtually useless. Thus, configure the scope options, along with the IP address and subnet mask that you configured earlier in this chapter.

In the following sections, you will learn how to configure and assign scope options on the DHCP server.

Understanding Option Assignment

You can control which DHCP options are doled out to clients in five (slightly overlapping) ways:

Predefined Options Predefined options are templates that are available in the Server, Scope, or Client Options dialog box.

Server Options Server options are assigned to all scopes and clients of a particular server. That means if there’s some setting you want all clients of a DHCP server to have, no matter what scope they’re in, this is where you assign it. Specific options (those that are set at the class, scope, or client level) will override server-l evel options. That gives you an escape valve; it’s a better idea, though, to be careful about which options you assign if your server manages multiple scopes.

Scope Options If you want a particular option value assigned only to those clients in a certain subnet, you should assign it as a scope option. For example, it’s common to specify different routers for different physical subnets; if you have two scopes corresponding to different subnets, each scope would probably have a separate value for the router option.

Class Options You can assign different options to clients of different types, that is, class options. For example, Windows 2000, XP, Vista, Windows 7, Windows 8/8.1, Windows 10/11, Server 2003/2003 R2, Server 2008/ 2008 R2, Server 2012/2012 R2,

Windows Server 2016, Server 2019, and Server 2022 machines recognize a number of

DHCP options that Windows 98, Windows NT, and macOS machines ignore, and vice versa. By defining a Windows 2000 or newer class (using the ipconfig /setclassid command you saw earlier), you could assign those options only to machines that report themselves as being in that class.

Client Options If a client is using DHCP reservations, you can assign certain options to that specific client. You attach client options to a particular reservation. Client options override scope, server, and class options. The only way to override a client option is to configure the client manually. The DHCP server manages client options.

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