dnsmasq dhcp options

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computing: software: dnsmasq: dhcp options

Notes

The command "dnsmasq --help" is supposed to return a list of valid DHCP sub-options for the "--dhcp-option" option, but it just returns a summary of all the available options as given in detail on the dnsmasq manpage. This page will be for reconstructing what that list should actually be, based on that page and any other sources found.

Options

The option numbers are specified in RFC 2132 and subsequent RFCs.

Usage:

• command line:
  • --dhcp-option=number,value
  • --dhcp-option=option:name,value
• dnsmasq.conf:
  • dhcp-option=number,value
  • dhcp-option=option:name,value

number	name	description
3	router	router to use for communication
42	ntp-server	network time protocol server

• The "option:name" format does not seem to work, at least in dnsmasq version 2.33. It may be fixed in later versions, or perhaps the syntax is more finicky than is indicated in the documentation.
• The special address 0.0.0.0 is taken to mean "the address of the machine running dnsmasq".
• Data types allowed are comma separated dotted-quad IP addresses, a decimal number, colon-separated hex digits and a text string.
• If the optional network-ids are given then this option is only sent when all the network-ids are matched.