Configuring and Unconfiguring a DHCP Server Using DHCP Manager

This section includes procedures for configuring and unconfiguring a server using DHCP Manager. Note that you must be running an X Window system such as CDE to use DHCP Manager.

The first time you run DHCP Manager on a system, the following screen is displayed to allow you to specify whether you want to configure a DHCP server or BOOTP relay agent.

Figure 10-1 Choose Server Configuration Dialog

Configuring DHCP Servers

When you configure a DHCP server, DHCP Manager starts the DHCP Configuration Wizard, which prompts you for information needed to configure the server. The initial screen of the wizard is shown in the following figure.

Figure 10-2 DHCP Configuration Wizard's Initial Screen

When you finish answering the wizard prompts, DHCP Manager creates the items listed in the following table.

Table 10-1 Items Created During DHCP Server Configuration

Item	Description	Contents
Service configuration file, /etc/default/dhcp	Records keywords and values for server configuration options.	Data store type and location, options used with in.dhcpd to start the DHCP daemon when system boots.
dhcptab file	DHCP Manager creates an empty filedhcptab if it does not already exist.	Macros and options with assigned values.
Locale macro, optional	Contains the local time zone's offset in seconds from Universal Time (UTC).	UTCoffst option
Server macro, named to match server's node name	Contains options whose values were set using input from administrator configuring the DHCP server. Options should apply to all clients using addresses owned by the server.	The Locale macro, plus the following options: Timeserv, set to point to the server's primary IP address LeaseTim, and LeaseNeg if you selected negotiable leases DNSdmain and DNSserv, if DNS is configured Hostname, which must not be assigned a value. The presence of this option indicates that the hostname must be obtained from the name service.
Network address macro, whose name is the same as the network address of client's network	Contains options whose values were set using input from administrator configuring the DHCP server. Options should apply to all clients residing on the network matching the macro name.	The following options: Subnet Router or RDiscvyF Broadcst, if the network is a LAN MTU NISdmain and NISserv, if NIS is configured NIS+dom and NIS+serv, if NIS+ is configured
Network table for the network.	Empty table is created until you create IP address for the network.	None, until you add IP addresses.
Links to the DHCP service script, /etc/init.d/dhcp.	Enables the DHCP daemon to start automatically when the system boots.	The following links are made: /etc/rc0.d/K34dhcp /etc/rc1.d/K34dhcp /etc/rc2.d/K34dhcp /etc/rc3.d/S34dhcp

How to Configure a DHCP Server (DHCP Manager)

1. Select the system you want to use as a DHCP server.

   Use the guidelines in "Making Decisions for Server Configuration".

2. Make decisions about your data store, lease policy, and router information.

   Use the guidelines in "Making Decisions for Server Configuration".

3. Become superuser on the server system.

4. Type the following command:

   #/usr/sadm/admin/bin/dhcpmgr &

5. Choose the option Configure as DHCP Server.

   This starts the DHCP Configuration Wizard, which guides you in configuring your server.

6. Select options or type requested information based on the decisions you made during the planning phase.

   If you have difficulty, click Help in the Wizard window to open your web browser and display help for the DHCP Configuration Wizard.

7. Click Finish to complete the server configuration when you have finished entering the requested information.

8. At the Start Address Wizard window, click Yes to begin configuring addresses for the server.

   The Address Wizard enables you to specify which addresses to place under control of DHCP.

9. Answer the prompts based on decisions made during the planning phase.

   See "Making Decisions for IP Address Management" for more information. If you have difficulty, click Help in the Wizard window to open your web browser and display help for the Add Addresses Wizard.

10. Review your selections, and click Finish to add the addresses to the network table.

    The network table is updated with records for each address in the range you specified.

You can add more networks to the DHCP server using the Network Wizard, as explained in "Adding DHCP Networks".

Configuring BOOTP Relay Agents

When you configure a BOOTP relay agent, DHCP Manager takes the following actions:

• Prompts you for IP addresses of DHCP server to which requests should be relayed.

• Edits /etc/default/dhcp, to specify the options needed for BOOTP relay service.

• Creates the following links to /etc/init.d/dhcp to enable the DHCP daemon to start when the system boots:

  • /etc/rc0.d/K34dhcp

  • /etc/rc1.d/K34dhcp

  • /etc/rc2.d/K34dhcp

  • /etc/rc3.d/S34dhcp

The following figure shows the screen displayed when you choose to configure a BOOTP relay agent.

Figure 10-3 Configure BOOTP Relay Dialog Box

How to Configure a BOOTP Relay Agent (DHCP Manager)

1. Select the system you want to use as a BOOTP relay agent.

   See "Selecting a Server for DHCP".

2. Become superuser on the server system.

3. Type the following:

   #/usr/sadm/admin/bin/dhcpmgr &

   If the system has not been configured as a DHCP server or BOOTP relay agent, the DHCP Configuration Wizard starts. If the system has already been configured as a DHCP server, you cannot configure it as a BOOTP relay agent unless you unconfigure the server first. See "Unconfiguring DHCP Servers and BOOTP Relay Agents".

4. Select Configure as BOOTP Relay.

   The Configure BOOTP Relay dialog box opens.

5. Type the IP address or hostname of one or more DHCP servers that are configured to handle BOOTP or DHCP requests received by this BOOTP relay agent, and click Add.

   After you click OK, notice that the DHCP Manager offers only the File menu to exit the application and the Service menu to manage the server. Other menu options are disabled because they are useful only on a DHCP server.

Unconfiguring DHCP Servers and BOOTP Relay Agents

When you unconfigure a DHCP server or BOOTP relay agent, DHCP Manager takes the following actions:

• Stops the DHCP daemon (in.dhpcd) process

• Removes the links that enable automatic starting when the system boots

• Removes the /etc/default/dhcp file, which records information about daemon startup and the data store location

The following figure shows the screen that is displayed when you choose to unconfigure a DHCP server.

Figure 10-4 Unconfigure Service Dialog Box

When you unconfigure a DHCP server you must decide what to do with the DHCP data files: dhcptab and the DHCP network tables. If the data is shared among servers, you should not remove the dhcptab and DHCP network tables because this could render DHCP unusable across your network. Data can be shared through NIS+ or on exported local file systems. The file /etc/default/dhcp records the data store used and its location.

You can unconfigure a DHCP server while leaving the data intact by not selecting any of the options to remove data. Unconfiguring while leaving the data intact in effect disables the DHCP server.

If you are certain that you want to remove the data, you can select an option to remove the dhcptab and network tables. If you had generated client names for the DHCP addresses, you can also elect to remove those entries from /etc/inet/hosts or the NIS+ hosts table.

Before you unconfigure a BOOTP relay agent, be sure that no clients rely on this agent to forward requests to a DHCP server.

How to Unconfigure a DHCP Server or BOOTP Relay Agent (DHCP Manager)

1. Become superuser.

2. Type the following:

   #/usr/sadm/admin/bin/dhcpmgr &

3. From the Services menu, choose Unconfigure.

   The Unconfigure Service dialog box is displayed. If the server is a BOOTP relay agent, the dialog box enables you to confirm your intention to unconfigure the relay agent. If the server is a DHCP server, you must decide what to do with the DHCP data by making selections in the dialog box. See Figure 10-4.

4. (Optional) Select options to remove data.

   If the server is using shared data (using NIS+ or files shared through NFS), do not select any options to remove the data. If the server is a DHCP server that is not using shared data, select one or both options to remove the data.

   See "Unconfiguring DHCP Servers and BOOTP Relay Agents" for more information about removing data.

5. Click OK to confirm.