dhcp server option
Function
The dhcp server option command sets user-defined option for an interface address pool.
The undo dhcp server option command deletes user-defined option from an interface address pool.
By default, no user-defined option is configured in an interface address pool.
Format
dhcp server option code [ sub-option sub-code ] { ascii ascii-string | hex hex-string | cipher cipher-string | ip-address ip-address &<1-8> }
undo dhcp server option [ code [ sub-option sub-code ] ]
Parameters
Parameter |
Description |
Value |
|---|---|---|
code |
Specifies the code for a user-defined option. |
The value is an integer that ranges from 1 to 254, except
values 1, 3, 6, 15, 44, 46, 50, 51, 52, 53, 54, 55, 57, 58, 59, 61,
82, 120, 121 and 184.
NOTE:
|
sub-option sub-code |
Specifies the code of a user-defined sub-option. |
The value is an integer that ranges from 1 to 254. For details about well-known options, see RFC 2132. |
ascii ascii-string |
Specifies the user-defined option code as an ASCII character string. |
The value is a string of 1 to 255 characters when sub-option is not specified, or a string of 1 to 253 characters when sub-option is specified. |
hex hex-string |
Specifies the user-defined option code as a hexadecimal string. |
The value is a hexadecimal string with an even number of digits, for example, hh or hhhh. If sub-option is not specified, the even number is in the range of 2 to 254. If sub-option is specified, the even number is in the range of 2 to 252. The value can be a combination of digits (0-9) and letters (A-F and a-f). |
cipher cipher-string |
Specifies the user-defined option code as a ciphertext character string. |
The value is a string, you can enter a character string in explicit text or cipher text.
No matter whether the character string is entered in explicit or cipher text, the character string is displayed in cipher text in the configuration file and in explicit text in packets. |
| ip-address ip-address | Specifies the user-defined option code as an IP address. |
The value is in dotted decimal notation. |
Usage Guidelines
Usage Scenario
This command applies to DHCP servers. The Option field in a DHCP packet carries control information and parameters, including basic information such as the DNS service, NetBIOS service, and IP address lease. If a DHCP server is configured with option, when a DHCP client applies for an IP address from an interface address pool, the client can obtain configurations in the Option field of the DHCP response packet from the DHCP server without having to configure the DNS service, NetBIOS service, or IP address lease separately.
The address of an interface address pool has been configured using the ip address command.
The DHCP server function has been enabled on the interface using the dhcp select interface command.
Precautions
- When the password is contained in option, the ascii or hex type is insecure. Set the option type to cipher. A secure password should contain at least two types of the following: lowercase letters, uppercase letters, number, and special characters. In addition, the password must consist of six or more than six characters.
- The dhcp server option command configures basic functions, such as the NetBIOS service and IP address lease. The system also provides commands to configure these functions separately. These commands take precedence over the dhcp server option command.
- To set user-defined option for a global address pool, run the option command.
Example
<AC6605> system-view [AC6605] dhcp enable [AC6605] interface vlanif 100 [AC6605-Vlanif100] ip address 10.10.10.10 24 [AC6605-Vlanif100] dhcp select interface [AC6605-Vlanif100] dhcp server option 64 hex 11
