vendor options

Glenn Satchell glenn.satchell at
Wed Sep 22 22:52:43 UTC 2010

On 09/23/10 04:55, Gaughan, Michael E (US SSA) wrote:
> I have been trying to use the ISC DHCP Server with an embedded DHCP
> Client (origin unknown). The Server serves up IP Addresses correctly but
> does not serve up the vendor options defined in the config file. I have
> been operating under the assumption that having received a
> ‘client-identifier’ (option 60) in the DHCP DISCOVER message, the DHCP
> Server would automatically include the ‘vendor-options’ (option 43) in
> the DHCP OFFER message. Am I mistaken?
> The parameter-request in the DHCP DISCOVER message from the DHCP Client
> does not contain option 43.
> Thanks in advance,
> Mike Gaughan

client-identifier and vendor-options are completely unrelated. dhcpd 
only returns those options the client asks for. The assumption being if 
it didn't ask then it probably doesn't know how to handle the option. 
This is the behaviour the RFC defines.

You can force the option 43 onto the parameter request list, and this 
will send it. Still no guarantee that the client will use it though. 2B 
in hex is 43 decimal.

Include this in an appropriate scope:

option dhcp-parameter-request-list = concat(option 
dhcp-parameter-request-list, 2b);

Glenn Satchell                            |  Miss 9: What do you
Uniq Advances Pty Ltd, Sydney Australia   |  do at work Dad?
mailto:glenn.satchell at         |  Miss 6: He just tel:0409-458-580   |  types random stuff.

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