User guide

88 Chapter 4. Configuring Special Features
Enable/Disable BootP
To allow BootP request processing for a particular client/subnet, use the command:
dhcp bootp allow <net>|<ipaddr>
To disallow BootP request processing for a particular client/subnet, type:
dhcp bootp disallow <net>|<ipaddr>
Use BootP to Specify the Boot Server
The following commands let the administrator specify the TFTP server (boot server) and boot file name. The
administrator should first configure the IP address of the TFTP server and file name (kernel) from which to
boot. This is particularly useful if the kernel in the routerÕs flash is corrupt or does not exist.
To set the IP address of the server and the file to boot from, use the commands:
dhcp bootp tftpserver [<net>|<ipaddr>] <tftpserver ipaddr>
dhcp bootp file [<net>|<ipaddr>] <file name>
To clear the IP address of the server and the file to boot from, use:
dhcp bootp tftpserver [<net>|<ipaddr>] 0.0.0.0
Example 1:
To set the global BootP server IP address to 192.168.254.7:
dhcp bootp tftpserver 192.168.254.7
Example 2:
To set the subnet 192.168.254.0 server IP address to 192.168.254.8:
dhcp bootp tftpserver 192.168.254.0 192.168.254.8
Example 3:
To set the client 192.168.254.21 server IP address to 192.168.254.9
dhcp bootp tftpserver 192.168.254.21 192.168.254.9
Example 4:
To set the subnet 192.168.254.0 boot file to Òkernel.100Ó:
dhcp bootp file 192.168.254.0 kernel.100
Example 5:
To clear the global BootP server IP address and file name:
dhcp bootp tftpserver 0.0.0.0
Example 6:
To clear the subnet 192.168.254.0 server IP address and file name:
dhcp bootp tftpserver 192.168.254.0 0.0.0.0
Defining Option Types
Concepts
A DHCP option is a code, length, or value. An option also has a ÒtypeÓ (byte, word, long, longint, binary, IP
address, string).
The subnet mask, router gateway, domain name, domain name servers, NetBios name servers are all DHCP
options. Refer to RFC 1533 if you require more information.