Configuring The Dhcp Server Security Functions - 3Com Switch 4800G 24-Port Configuration Manual

806 C 57: DHCP S
HAPTER
Configuring the DHCP
Server Security
Functions
C
ERVER ONFIGURATION
Define existing DHCP options. Some options have no unified definitions in RFC
■
2132; however, vendors can define such options as needed. The self-defined
DHCP option enables DHCP clients to obtain vendor-specific information.
Extend existing DHCP options. When the current DHCP options cannot meet
■
the customers' requirements (for example, you cannot use the dns-list
command to configure more than eight DNS server addresses), you can
configure a self defined option for extension.
Follow these steps to configure a self-defined DHCP option in the DHCP address
pool:
To do...
Enter system view
Enter DHCP address pool view dhcp server ip-pool
Configure a self-defined
DHCP option
Table 61 Description of common options
Option Option name
3 Router Option
6 Domain Name Server Option
15 Domain Name
44 NetBIOS over TCP/IP Name Server
Option
46 NetBIOS over TCP/IP Node Type
Option
51 IP Address Lease Time
58 Renewal (T1) Time Value
59 Rebinding (T2) Time Value
66 TFTP server name
67 Bootfile name
43 Vendor Specific Information
c
CAUTION:
Be cautious when configuring self-defined DHCP options because such
■
configuration may affect the DHCP operation process.
When you use self-defined option (Option 51) to configure the IP address lease
■
duration, convert the lease duration into seconds in hexadecimal notation.
This configuration is necessary to secure DHCP services on the DHCP server.
Use the command...
system-view
pool-name
option code { ascii
ascii-string | hex
hex-string&<1-16> |
ip-address
ip-address&<1-8> }
Corresponding
command
gateway-list
dns-list
domain-name
nbns-list
netbios-type
expired
expired
expired
tftp-server
bootfile-name
-
Remarks
-
-
Required
No DHCP option is configured
by default.
Command
parameter
ip-address
ip-address
ascii
ip-address
hex
hex
hex
hex
ascii
ascii
hex