DHCPv6 tftp server and filename options

Shane Kerr Shane_Kerr at isc.org
Fri Jan 18 10:12:42 UTC 2008


Jens Freimann wrote:
> I'm trying to configure dhcpd 4.0.0b1 for stateless DHCPv6, i.e. I want
> to get an address by stateless adress autoconfiguration and the IP 
> address of my tftp server and the bootfile name from a DHCPv6 server.
> So, what I want to do is, send an information-request and get a reply
> with tftp-server and a filename. 
> I'm a bit confused about how to configure dhcpd with the appropriate
> option settings though. There are the old DHCP options, DHCPv6 options
> and docsis (cable labs) dhcp options.
> RFC 3736 [0] doesn't say anyting about TFTP server and filename options. Is
> there really no way to do this with DHCPv6?
> I found and old IETF draft "DHCPv6 Support for Remote Boot - 
> draft-ietf-dhc-dhcpv6-opt-rboot-00.txt" [1] but it expired in 2003. 
> It would be nice if somebody could give me a hint. Any ideas?

My recommendation would be to use the DOCSIS 3.0 vendor-specific options.

CableLabs publishes their standards, and you can Google for "cann dhcp-reg" to
get the document with their options:


You can create an option space for this using the normal DHCP configuration


# Define the DOCSIS option space.
option space docsis code width 2 length width 2;
option docsis.tftp-servers code 32 = array of ip6-address;
option docsis.cablelabs-configuration-file code 33 = text;
option docsis.cablelabs-syslog-servers code 34 = array of ip6-address;
option docsis.device-id code 36 = string;


DOCSIS also defines some time options, but I would recommend using the shiny new
IETF option for this (RFC 4883 - Timezone Options for DHCP, and RFC 4075 - SNTP
Configuration Option for DHCP).

I would also recommend using DHCP 4.0.0 final rather than the beta. We actually
fixed the Information-Request support in the final release. :-/


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