>From: Morten Andersen <morten at vianett.no>
>To: "dhcp-users at isc.org" <dhcp-users at isc.org>
>
>> Failing any specific option you could always extract that piece of
>> information from the packet directly. The function packet() is
>> described in the dhcp-options man page.
>>
>> packet (offset, length)
>>
>> The packet operator returns the specified portion of the
>> packet being considered, or null in contexts where no
>> packet is being considered. Offset and length are
>> applied to the contents packet as in the substring opera-
>> tor.
>
>Thank you for your response. This sounds like a solution that can work
> but I can`t find any information about the packet() function,
packet extracts a specified chunk from the packet currently being
processed. You'll need to use a packet capture to look at the contents
of the packet and work out the bytes you need.
The snippet above is from the dhcp-options man page.
> but I found "RELAY AGENT INFORMATION OPTION" in the dhcp-options man
> page and I think this can help me. One tiny problem now is that the
> man-page does not mention how to set the parameters on the dhcrelay
> agents. Anyone? :)
>
man dhcrelay
...
RELAY AGENT INFORMATION OPTIONS
If the -a flag is set the relay agent will append an agent
option field to each request before forwarding it to the
server. Agent option fields in responses sent from servers
to clients will be stripped before forwarding such responses
back to the client.
The agent option field will contain two agent options: the
Circuit ID suboption and the Remote ID suboption.
Currently, the Circuit ID will be the printable name of the
interface on which the client request was received. The
client supports inclusion of a Remote ID suboption as well,
but this is not used by default.
Maybe time to go look at the source...
regards,
-glenn