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How to configure DHCP options for DHCP clients?

By default, Vigor Router will be a DHCP server and automatically assign an IP address to the DHCP clients on LAN. From LAN >> General Setup >> Details Page >> DHCP Server Configuration, Network Administrator may also set up some basic DHCP options, including:

  • option 1- Subnet Mask
  • option 3- Router (Gateway IP Address)
  • option 6- Domain Name Server
  • option 51- Lease Time

To configure more DHCP options which are not listed above,

1. Go to LAN >> General Setup, click on "Advanced" button.

a screenshot of LAN setup page on DrayOS    

2. In LAN >> General Setup >> Advanced page, add a new DHCP option to Customized List by:

  1. Click Enable
  2. Select the LAN Interfaces to which this option should apply
  3. Enter the DHCP Option Number
  4. Select a Data Type according to the option requirements
  5. Enter the Data for DHCP option
  6. Click Add to add the option to Customized List.
a screenshot of LAN setup page on DrayOS    

Note: ACSII character " and \ are forbidden due to security concern. Please use HEX 22 and 5C instead.

3. After clicking OK to apply, the DHCP client on LAN will see the DHCP option provided in the DHCP Offer.

wireshark screenshot    

DHCP Option Examples

Vigor Router supports three kinds of datatype: ASCII characters, Hexadecimal digits, and Address List. Note that every DHCP option has their required datatype and format. The list below shows some of the DHCP options and their required data.


 Option Name




 Extensions Path


The path name, file name, and extension of the specified file, for example, "/path/2925001.cfg"


 Static Route

 Address List

A pair of IP address separated by ",", where the first one is the destination IP, and the second is the router's IP, for example, ","


 TFTP Server Name


The name of the TFTP server.


 Bootfile Name


The file name presented in hexadecimal format.


 Domain Search


The domain suffixes presented in hexadecimal with a number indicate the length in front of it. For example, "draytek.com" should be presented as "076472617974656b03636f6d" where 07 means there are 7 characters followed, 6472617974656b is "draytek", 03 means there are 3 characters followed, and 636f6d is "com"


 Classless Static Route  Option


The width of subnet mask, the significant portion of the subnet number, and the IP address of the router presented in hexadecimal value. For example, a route " via" should be presented as "18ac10c4ac100201", where 18 is the "24" in hex, ac10c4 is "172.16.196", and ac100201 is


 TFTP Server Address

 Address List

The IP address of TFTP server.

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