[Dnsmasq-discuss] Configuring Dnsmasq for DHCP option 125
simon at thekelleys.org.uk
Tue Oct 5 13:41:54 BST 2010
art.cremin at lakecommunications.com wrote:
> Using Dnsmasq 2.55, I need to respond to a DHCP discovery containing
> option 124 with an enterprise number. My response should be an offer
> containing Option 125, enterprise number, data length, and a
> vendor-specific data block.
Are you sure? By my reading of RFC3925 this vendor-specific data block
actually contains one or more suboptions, each of which has a code
number. Dnsmasq gets told the individual sub-options and creates the
data block out of them.
> Unfortunately I cannot understand the man
> page well enough to answer the following question for myself!
> How do I configure Dnsmasq to make this response?
> Art Cremin
Specifying the option looks like this.
dhcp-option= vi-encap:10, 20, <data>
this becomes active when a DHCP packet containing option 124 with
enterprise 10 in it is received, and it returns option 125 with a
section for enterprise 10. That section contains a sub-option 20 with
the given data.
The data can be a string, or hex or an IP address or a decimal number.
dhcp-option=vi-encap:10, 20, "hello mum"
dhcp-option=vi-encap:10, 20. 11:22:33:44
You can specify more than one dhcp-option for an enterprise number and
they will be packed together as a set of sub-options. You can also
specify options for more than one enterprise number and they will be
included as requested by the received option 124.
This stuff takes a bit of thinking about, and I'm not sure my
explanation is very good, so please come back for more help if you need
to. A more complete description of what data you're trying to send would
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