Working With IP Addresses in the DHCP Service (Task Map)

You can use DHCP Manager or the pntadm command to add IP addresses, modify address properties, and remove addresses from the DHCP service. Before you work with IP addresses, you should refer to Table 15-4 to become familiar with IP address properties. The table provides information for users of DHCP Manager and pntadm.

Note - Table 15-4 includes examples of using pntadm to specify IP address properties while adding and modifying IP addresses. Refer also to the pntadm(1M) man page for more information about pntadm.

The following task map lists tasks that you must perform to add, modify, or remove IP addresses. The task map also contains links to the procedures used to carry out the tasks.

The following table lists and describes the properties of IP addresses.

Table 15-4 IP Address Properties

Adding IP Addresses to the DHCP Service

Before you add IP addresses, you must add the network that owns the addresses to the DHCP service. See Adding DHCP Networks for information about adding networks.

You can add addresses with DHCP Manager or the pntadm command.

On networks that are already managed by the DHCP service, you can add addresses in several ways with DHCP Manager:

• Add a single IP address – Place one new IP address under DHCP management.

• Duplicate an existing IP address – Copy the properties of an existing IP address managed by DHCP, and supply a new IP address and client name.

• Add a range of multiple IP addresses – Use the Address Wizard to place a series of IP addresses under DHCP management.

The following figure shows the Create Address dialog box. The Duplicate Address dialog box is identical to the Create Address dialog box, except that the text fields display the values for an existing address.

Figure 15-8 Create Address Dialog Box in DHCP Manager

The following figure shows the first dialog of the Add Addresses to Network wizard, used to add a range of IP addresses.

Figure 15-9 Add Addresses to Network Wizard in DHCP Manager

How to Add a Single IP Address (DHCP Manager)

1. In DHCP Manager, select the Addresses tab.

   See How to Start and Stop DHCP Manager for information about DHCP Manager.

2. Select the network where the new IP address is to be added.
3. Choose Create from the Edit menu.

   The Create Address dialog box opens.

4. Select or type values for the address settings on the Address and Lease tabs.

   Select the Help button to open a web browser to display help for the dialog box. Also, see Table 15-4 for detailed information about the settings.

5. Click OK.

How to Duplicate an Existing IP Address (DHCP Manager)

1. In DHCP Manager, select the Addresses tab.

   See How to Start and Stop DHCP Manager for information about DHCP Manager.

2. Select the network where the new IP address is located.
3. Select the address with properties that you want to duplicate.
4. Choose Duplicate from the Edit menu.
5. Specify the new IP address in the IP Address field.
6. (Optional) Specify a new client name for the address.

   You cannot use the same name that is used by the address that you are duplicating.

7. (Optional) Modify other option values, if necessary.

   Most other option values should remain the same.

8. Click OK.

How to Add Multiple IP Addresses (DHCP Manager)

1. In DHCP Manager, select the Addresses tab.

   See How to Start and Stop DHCP Manager for information about DHCP Manager.

2. Select the network where the new IP addresses are to be added.
3. Choose Address Wizard from the Edit menu.

   The Add Addresses to Network dialog box prompts you to provide values for the IP address properties. See Table 15-4 for more information about the properties, or select the Help button in the dialog box. Making Decisions for IP Address Management (Task Map) includes more extensive information.

4. Click the right arrow button as you finish each screen, and click Finish on the last screen.

   The Addresses tab is updated with the new addresses.

How to Add IP Addresses (pntadm)

1. Become superuser or assume a role or user name that is assigned to the DHCP Management profile.

   For more information about the DHCP Management profile, see Setting Up User Access to DHCP Commands.

   Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

2. Add IP addresses by typing a command of the following format:

   # pntadm -A ip-address options network-address

   Refer to the pntadm(1M) man page for a list of options you can use with pntadm -A. In addition, Table 15-4 shows some sample pntadm commands that specify options.

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   Note - You can write a script to add multiple addresses with pntadm. See Example 18-1 for an example.

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Modifying IP Addresses in the DHCP Service

You can modify any of the address properties described in Table 15-4 by using DHCP Manager or the pntadm -M command. See the pntadm(1M) man page for more information about pntadm -M.

The following figure shows the Address Properties dialog box that you use to modify IP address properties.

Figure 15-10 Address Properties Dialog Box in DHCP Manager

The following figure shows the Modify Multiple Addresses dialog box that you use to modify multiple IP addresses.

Figure 15-11 Modify Multiple Addresses Dialog Box in DHCP Manager

How to Modify IP Address Properties (DHCP Manager)

1. In DHCP Manager, select the Addresses tab.

   See How to Start and Stop DHCP Manager for information about DHCP Manager.

2. Select the IP address's network.
3. Select one or more IP addresses to modify.

   If you want to modify more than one address, press the Control key while you click with the mouse to select multiple addresses. You can also press the Shift key while you click to select a block of addresses.

4. Choose Properties from the Edit menu.

   The Address Properties dialog box or the Modify Multiple Address dialog box opens.

5. Change the appropriate properties.

   Click the Help button, or refer to Table 15-4 for information about the properties.

6. Click OK.

How to Modify IP Address Properties (pntadm)

1. Become superuser or assume a role or user name that is assigned to the DHCP Management profile.

   For more information about the DHCP Management profile, see Setting Up User Access to DHCP Commands.

   Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

2. Modify IP address properties by typing a command of the following format:

   # pntadm -M ip-address options network-address

   Many options can be used with the pntadm command, which are documented in the pntadm(1M) man page.

   Table 15-4 shows some sample pntadm commands that specify options.

Removing IP Addresses From the DHCP Service

At times, you might want the DHCP service to stop managing a particular IP address or group of addresses. The method that you use to remove an address from DHCP depends on whether you want the change to be temporary or permanent.

• To temporarily prevent the use of addresses, you can mark the addresses as unusable in the Address Properties dialog box as described in Marking IP Addresses as Unusable by the DHCP Service.

• To permanently prevent the use of addresses by DHCP clients, delete the addresses from the DHCP network tables, as described in Deleting IP Addresses From the DHCP Service.

Marking IP Addresses as Unusable by the DHCP Service

You can use the pntadm -M command with the -f UNUSABLE option to mark addresses as unusable.

In DHCP Manager, you use the Address Properties dialog box, shown in Figure 15-10, to mark individual addresses. You use the Modify Multiple Addresses dialog box, show in Figure 15-11, to mark multiple addresses, as described in the following procedure.

How to Mark IP Addresses as Unusable (DHCP Manager)

1. In DHCP Manager, select the Addresses tab.

   See How to Start and Stop DHCP Manager for information about DHCP Manager.

2. Select the IP address's network.
3. Select one or more IP addresses to mark as unusable.

   If you want to mark more than one address as unusable, press the Control key while you click with the mouse to select multiple addresses. You can also press the Shift key while you click to select a block of addresses.

4. Choose Properties from the Edit menu.

   The Address Properties dialog box or the Modify Multiple Address dialog box opens.

5. If you are modifying one address, select the Lease tab.
6. Select Address is Unusable.

   If you are editing multiple addresses, select Mark All Addresses Unusable.

7. Click OK.

How to Mark IP Addresses as Unusable (pntadm)

1. Become superuser or assume a role or user name that is assigned to the DHCP Management profile.

   For more information about the DHCP Management profile, see Setting Up User Access to DHCP Commands.

   Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

2. Mark IP addresses as unusable by typing a command of the following format:

   # pntadm -M ip-address -f UNUSABLE network-address

   For example, to mark address 10.64.3.3 as unusable, type:

   pntadm -M 10.64.3.3 -f UNUSABLE 10.64.3.0

Deleting IP Addresses From the DHCP Service

You should delete IP addresses from the DHCP network tables if you no longer want the address to be managed by DHCP. You can use the pntadm -D command or DHCP Manager's Delete Address dialog box.

The following figure shows the Delete Address dialog box.

Figure 15-12 Delete Address Dialog Box in DHCP Manager

How to Delete IP Addresses From DHCP Service (DHCP Manager)

1. In DHCP Manager, select the Addresses tab.

   See How to Start and Stop DHCP Manager for information about DHCP Manager.

2. Select the IP address's network.
3. Select one or more IP addresses to delete.

   If you want to delete more than one address, press the Control key while you click with the mouse to select multiple addresses. You can also press the Shift key while you click to select a block of addresses.

4. Choose Delete from the Edit menu.

   The Delete Address dialog box lists the address that you selected so that you can confirm the deletion.

5. If you want to delete the host names from the hosts table, select Delete From Hosts Table.

   If the host names were generated by DHCP Manager, you might want to delete the names from the hosts table.

6. Click OK.

How to Delete IP Addresses From the DHCP Service (pntadm)

1. Become superuser or assume a role or user name that is assigned to the DHCP Management profile.

   For more information about the DHCP Management profile, see Setting Up User Access to DHCP Commands.

   Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

2. Delete IP addresses by typing a command of the following format:

   # pntadm -D ip-address options network-address

   If you include the -y option, the host name is deleted from the name service that maintains the host name.

   For example, to delete address 10.64.3.3 from network 10.64.3.0, and delete the corresponding host name, type:

   pntadm -D 10.64.3.3 -y 10.64.3.0

Assigning a Reserved IP Address to a DHCP Client

The Solaris DHCP service attempts to provide the same IP address to a client that has previously obtained an address through DHCP. However, sometimes an address has already been reassigned to another client.

Routers, NIS or NIS+ servers, DNS servers, and other hosts that are critical to the network should not be DHCP clients. Hosts that provide services to the network should not rely on the network to obtain their IP addresses. Clients such as print servers or file servers should have consistent IP addresses as well. These clients can receive their network configurations and also be assigned a consistent IP address from the DHCP server.

You can set up the DHCP server to supply the same IP address to a client each time the client requests its configuration. You reserve the IP address for the client by manually assigning the client's ID to the address that you want the client to use. You can set up the reserved address to use either a dynamic lease or a permanent lease. If the client's address uses a dynamic lease, you can easily track the use of the address. A diskless client is an example of a client that should use a reserved address with a dynamic lease. If the client's address uses a permanent lease, you cannot track address use. Once a client obtains a permanent lease, the client does not contact the server again. The client can obtain updated configuration information only by releasing the IP address and restarting the DHCP lease negotiation.

You can use the pntadm -M command or DHCP Manager's Address Properties dialog box to set up lease properties.

The following figure shows the Lease tab of the Address Properties dialog box, which is used to modify the lease.

Figure 15-13 Address Properties Lease Tab in DHCP Manager

How to Assign a Consistent IP Address to a DHCP Client (DHCP Manager)

1. In DHCP Manager, select the Addresses tab.

   See How to Start and Stop DHCP Manager for information about DHCP Manager.

2. Select the appropriate network.
3. Double-click the IP address that you want to the client to use.

   The Address Properties window opens.

4. Select the Lease tab.
5. In the Client ID field, type the client ID.

   The client ID is derived from the client's hardware address. See the Client ID entry in Table 15-4 for more information.

6. Select the Reserved option to prevent the IP address from being reclaimed by the server.
7. In the Lease Policy area of the window, select Dynamic or Permanent assignment.

   Select Dynamic if you want the client to negotiate to renew leases, which enables you to track when the address is used. Because you selected Reserved, the address cannot be reclaimed even when a dynamic lease is assigned. You do not need to specify an expiration date for this lease. The DHCP server calculates the expiration date by using the lease time.

   If you select Permanent, you cannot track the use of the IP address unless you enable transaction logging.

8. Click OK.

How to Assign a Consistent IP Address to a DHCP Client (pntadm)

1. Become superuser or assume a role or user name that is assigned to the DHCP Management profile.

   For more information about the DHCP Management profile, see Setting Up User Access to DHCP Commands.

   Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

2. Set the lease flags by typing a command of the following format:

   # pntadm -M ip-address -i client-id -f MANUAL+BOOTP network-address

   For example, to enable the Solaris DHCP client whose MAC address is 08:00:20:94:12:1E to always receive IP address 10.21.5.12, you would type:

   pntadm -M 10.21.5.12 -i 0108002094121E -f MANUAL+BOOTP 10.21.0.0

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   Tip - Refer to the Client ID entry in Table 15-4 for more information about how to determine client identifiers.

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