Subnet Management

You use the DNS/DHCP Management Utility to create and set up a DHCP Subnet object for each of the subnets to which you will assign addresses.

A Subnet object's specific DHCP options and configuration parameters apply to the entire subnet and override global options.

The Subnet Management role consists of the following tasks:

• Creating a Subnet object
• Viewing or Modifying a Subnet Object
• Deleting a Subnet Object

Creating a Subnet object

1. Click DHCP Management > Subnet Management to open the Subnet Management window in the main panel.

2. Select Create Subnet from the drop-down menu and click OK to open the Create Subnet window.

3. Enter a unique subnet name.

4. Select the eDirectory context where the new subnet record will be stored.

5. Enter a subnet address, a subnet mask, and the name of a default DHCP server in the fields provided.

   The default DHCP server field designates the principal DHCP server for a subnet. This server is assigned all address ranges created under the subnet, unless a different server is specified when the range is created. The default server is the only server that responds to BOOTP requests for the subnet.

6. Click Create.

   A message indicates that the new subnet has been created.

   IP address objects are simultaneously created to exclude routing and broadcast addresses.

Viewing or Modifying a Subnet Object

1. Click DHCP Management > Subnet Management to open the Subnet Management window in the main panel.

2. Select View/Modify Subnet from the drop-down menu and click OK to open the View/Modify Subnet window.

3. Select the Subnet object from the drop-down menu.

4. Click OK.

   You are led through a set of steps by which you can modify the following parameters:

   • DNS Zone for Dynamic Update: Specifies the DNS zone where dynamic updating will occur. The specified DNS zone is then notified of any changes to the subnet.
   • Domain Name: Specifies the domain name that will be combined with the hostname received from the client computer. This name will be given to DNS during dynamic DNS update. The domain name must be part of the zone specified for dynamic DNS.
   • Subnet Pool Preference: Specifies the subnet pool to be used by the subnet. This parameter setting is optional. Subnet pools enable the DHCP server to assign addresses to multiple logical networks on a single physical network. A subnet pool groups logical networks.
   • Default DHCP Server: Specifies a default DHCP server that will assign address ranges for the subnet. This server is also the only server that will respond to BOOTP requests for the subnet.
   • Comments: Provides an area for comment information about the subnet. This is an optional parameter.
   • Lease Type: Specifies the length of time for an address assignment. A lease type can be permanent or timed. Permanent leases never expire; the client is assigned an IP address for an indefinite period. Timed leases are defined in days, hours, and minutes. Timed leases expire, unless the client renews the lease.
   • Set Boot Parameter Options: Check this to specify the Server Address, Server Name, and Boot File Name for the BOOTP service. This information, provided at boot time, includes the address and name of a server the client can contact for a boot image, as well as a boot filename.
   • Other DHCP Options: To configure an option, complete the following steps:
     • Click Modify to open the DHCP options page that lists the available DHCP Options.
     • Select the DHCP option and provide the necessary DHCP information.
     • Click Add.

     To remove a DHCP option:

     • Check the Select column of the DHCP option you want to remove and click Delete.

Deleting a Subnet Object

1. Click DHCP Management > Subnet Management to open the Subnet Management window in the main panel.

2. Select Delete Subnet from the drop-down menu and click OK to open the Create Subnet window.

   • To remove all the Subnet objects in the list, check the top-level check box and click Delete.
   • To remove one or more Subnet objects, check the check box next to it and click Delete.