Table of Contents

Configuring BOOTP

BOOTP (BOOTstrap Protocol) was originally created for loading diskless computers. It was later used to allow a host to obtain all the required TCP/IP information to use the Internet. BOOTP allows a host to broadcast a request onto the network, and obtains information required from a BOOTP server. The BOOTP server is a computer that listens for incoming BOOTP requests and generates responses from a configuration database for the BOOTP clients on that network. BOOTP differs from DHCP in that it has no concept of lease or lease expiration. All IP addresses allocated by a BOOTP server are permanent.

You can configure Network Registrar to act like a BOOTP server. In addition, although BOOTP normally requires static address assignments, you can choose to either reserve IP addresses (and, therefore, use static assignments) or have IP addresses dynamically allocated for BOOTP clients.

Note   Network Registrar supports the BOOTP-only protocol, not TFTP. Often older versions of BOOTP use both protocols.

Table 12-1 lists the BOOTP configuration tasks described in this chapter and the sections where you can find more information about them.

About BOOTP

When you configure the DHCP server to return a BOOTP packet, be aware that BOOTP requires information in the DHCP packet in fields other than the option space. BOOTP devices often need information in the file (the bootfile), siaddr (the server's IP address), or sname (server's host name) fields of the DHCP packet (see RFC 2131).

Every Network Registrar DHCP policy has fields that allow you to configure the information you want returned directly in the file, siaddr, or sname fields. Network Registrar's DHCP server also supports a configuration parameter that allows you to configure the policy options and determine which of the fields' file, sname, or siaddr you want returned to the BOOTP device.

Network Registrar supports an analogous configuration parameter that allows you to configure which options and which of the fields (file, sname, or siaddr) you want returned to the DHCP client. This is in addition to any options requested by the DHCP clients in the dhcp-parameter-request option in the DHCP request. Thus, you can configure both the BOOTP and DHCP response packets appropriately for your devices.

Step 1   Decide the values that you want in the BOOTP packet reply fields:

• siaddr—The server's IP address.
  
  
• file—The name of the bootfile.
  
  
• sname—The optional server host name.
  
  

Step 2   Decide the list of options and their values that you want returned to the BOOTP client.

Step 3   Set the following values in the policy you want associated with the BOOTP request:

• The fields—Packet-siaddr, packet-file-name, packet-server-name that you want sent to the BOOTP client.
  
  
• The option values—such as servers and domain name that you want returned to the BOOTP client.
  
  
• The list of fields and options you want returned to the BOOTP client.
  
  

Step 4   Enable the associated scope or scopes for BOOTP processing.

Enable dynamic BOOTP processing if you want to have this scope provide an address for any BOOTP client that requests one. If you do not enable dynamic BOOTP, you will need to make reservations for each BOOTP client for which you want this scope to provide an address.

Enabling BOOTP for a Scope

You can enable BOOTP processing for a scope.

Using the GUI:

Step 1   In the Policies tab of the DHCP Server Properties dialog box (Figure 7-2), configure a packet to contain the information that BOOTP requires.

Step 2   In the Edit Options dialog box, select the options you want.

Step 3   Click the Send to BOOTP clients check box.

Step 4   If you select the Always send to DHCP clients check box, the DHCP server sends an option back in the DHCP reply packet regardless of whether the client requested the option.

Step 5   Click OK.

Step 6   In the Advanced tab of the DHCP Scope Properties dialog box, select the Enable BOOTP check box.

Step 7   If you want dynamic IP address assignment, select the check box, otherwise create reservations. (For details on making reservations, see the "Reserving a Lease" section.)

Step 8   Click OK.

Step 9   Reload the DHCP server.

Using the CLI:

You use the policy create and policy set commands to configure BOOTP.

Step 1   Set the policy fields. Specify the boot-reply options as a comma-separated list of strings. Specify the name of the option or field. The options have regular names, whereas the fields have names such as packet-siaddr, packet-file-name, and packet-server-name.

nrcmd> policy MyPolicy create 
nrcmd> policy MyPolicy set packet-siaddr=192.168.1.5 
nrcmd> policy MyPolicy set packet-file-name=mybootfile.bin 
nrcmd> policy MyPolicy set packet-server-name=servername 
nrcmd> policy MyPolicy set bootp-reply-options=packet-siaddr, 
        packet-file-name,domain-name,domain-name
-servers 
 

Step 2   Set the correct option values. The setOption method requires spaces (not equal signs) before values.

nrcmd> policy MyPolicy setOption option value 
 

Step 3   Enable BOOTP.

nrcmd> scope MyScope enable bootp 
 

Step 4   Enable dynamic BOOTP.

nrcmd> scope MyScope enable dynamic-bootp 
 

Moving or Decommissioning a BOOTP Client

When you move or decommission a BOOTP client, you can reuse its lease. To decommission a BOOTP client, you actually re-activate a de-activated lease.

Using the GUI:

Step 1   From the Server Manager window, select the scope for which you want to move or decommission a BOOTP client.

Step 2   On the Leases tab, select the de-activated lease you want to re-activate.

Step 3   Click the Lease Properties button (or double-click the lease) to open the Lease Properties dialog box (Figure 12-1).

Step 4   Click the Force available button.

Step 5   Deselect the Deactivate lease check box.

Step 6   Click OK.

Step 7   Click the Refresh list button.

Step 8   Click OK.

Using the CLI:

Use the lease force-available command to make a de-activated lease available again.

nrcmd> lease 5.5.0.14 force-available 
 

Using Dynamic BOOTP

When you use dynamic BOOTP, there are additional restrictions placed on the address usage in such scopes, because BOOTP clients are allocated IP addresses permanently and receive leases that never expire.

When a server, whose scope does not have the dynamic-bootp option enabled, goes to the Partner Down regime, it can allocate any available IP address from that scope, no matter whether it was initially available to the main or backup server. However, when the dynamic-bootp option is enabled, the main server and backup servers can only allocate their own addresses. Consequently scopes that enable the dynamic-bootp option require more addresses to support failover.

When using dynamic BOOTP, do the following:

• Segregate dynamic BOOTP clients to a single scope. Disable DHCP clients from using that scope with the scope name disable dhcp command.
  
  
• Use the dhcp set failover-dynamic-bootp-backup-percentage command to allocate a greater percentage of addresses to the backup server for this scope, as much as 50 percent higher than a regular backup percentage.
  
  

Every Network Registrar DHCP policy has fields that allow you to configure the information you want returned directly in the file, siaddr, or sname fields. Network Registrar's DHCP server also supports a configuration parameter that allows you to configure the policy options and determine which of the fields' file, sname, or siaddr you want returned to the BOOTP device.

Network Registrar supports an analogous configuration parameter that allows you to configure which options and which of the fields (file, sname, or siaddr) you want returned to the DHCP client. This is in addition to any options requested by the DHCP clients in the dhcp-parameter-request option in the DHCP request. Thus, you can configure both the BOOTP and DHCP response packets appropriately for your devices.

Step 1   Decide the values that you want in the BOOTP packet reply fields:

• siaddr—The server's IP address.
  
  
• file—The name of the bootfile.
  
  
• sname—The optional server host name.
  
  

Step 2   Decide the list of options and their values that you want returned to the BOOTP client.

Step 3   Set the following values in the policy you want associated with the BOOTP request:

• The fields—Packet-siaddr, packet-file-name, packet-server-name that you want sent to the BOOTP client.
  
  
• The option values—such as servers and domain name that you want returned to the BOOTP client.
  
  
• The list of fields and options you want returned to the BOOTP client.
  
  

Step 4   Enable the associated scope or scopes for BOOTP processing.

Enable dynamic BOOTP processing if you want to have this scope provide an address for any BOOTP client that requests one. If you do not enable dynamic BOOTP, you will need to make reservations for each BOOTP client for which you want this scope to provide an address.

Enabling BOOTP for a Scope

You can enable BOOTP processing for a scope.

Using the GUI:

Step 1   Go to the Policies tab of the DHCP Server Properties dialog box for the server.

Step 2   Click Edit Options to add the BOOTP-compatible options that apply. Select the Send to BOOTP clients check box. (If you select the Always send to DHCP clients check box, the DHCP server sends an option back in the DHCP reply packet regardless of whether the client requested the option.)

Step 3   Click OK, commit the change, and close the dialog box.

Step 4   Open the properties for the applicable scope and go to the Advanced tab.

Step 5   Select the Enable BOOTP check box. If you want dynamic IP address assignment, select the Dynamic BOOTP check box, otherwise create reservations (see the "Reserving a Lease" section.)