3Com 4800G Series, Configuration Manual

Page: 806 / 1246

806 C
HAPTER
57: DHCP S
ERVER
C
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:
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.
Configuring the DHCP
Server Security
Functions
This configuration is necessary to secure DHCP services on the DHCP server.
To do… Use the command… Remarks
Enter system view system-view -
Enter DHCP address pool view dhcp server ip-pool
pool-name
-
Configure a self-defined
DHCP option option code { ascii
ascii-string | hex
hex-string &<1-16> |
ip-address
ip-address &<1-8> }
Required
No DHCP option is configured
by default.
Table 61 Description of common options
Option Option name
Corresponding
command Command
parameter
3 Router Option gateway-list ip-address
6 Domain Name Server Option dns-list ip-address
15 Domain Name domain-name ascii
44 NetBIOS over TCP/IP Name Server
Option nbns-list ip-address
46 NetBIOS over TCP/IP Node Type
Option netbios-type hex
51 IP Address Lease Time expired hex
58 Renewal (T1) Time Value expired hex
59 Rebinding (T2) Time Value expired hex
66 TFTP server name tftp-server ascii
67 Bootfile name bootfile-name ascii
43 Vendor Specific Information - hex