Re: DHCP Option 82 And Classes In Depth Understanding

Hi,

I didn't get any reply to my question up to this moment. I hope I will get.

Best Regards,

On Tue, Oct 27, 2009 at 4:52 PM, ALL From_NJ <all.from.nj_at_gmail.com> wrote:

> Was there an answer to this? Just wanting to make sure I did not miss it
> ...
>
>
>
> On Mon, Oct 26, 2009 at 5:19 AM, karim jamali <karim.jamali_at_gmail.com>wrote:
>
>> Dear Experts,
>>
>> I was reading through the DOC CD about DHCP Option 82, and the ability to
>> create DHCP classes. Please correct me if I am wrong with the following
>> statements:
>>
>> 1)DHCP request is a broadcasted on the LAN segment and it is up to the
>> gateway (giaddress field) to convert it to a unicast ip address (relaying
>> the information) when the ip helper-address is used pointing towards the
>> server.
>>
>> 2)Based on this giaddress,the server knows that the client from a certain
>> subnet requested an ip address, thus it provides it with an ip address
>> from
>> that subnet.
>>
>> 2)Option 82 gives another method to segregate clients other than the
>> subnet
>> in which users reside, i.e. having two hosts on a common vlan (subnet) it
>> is
>> still possible to give each host an ip address from a different range
>> which
>> corresponds to a different option 82 (hexadecimal value).This can happen
>> by
>> defining a common pool and dividing the pool into classes, where each
>> class
>> is matched by the option 82 value and corresponds to a different range of
>> ip
>> addresses.
>>
>> 3)The server will examine the relay agent information, and check it
>> against
>> the list of classes relay-information to find a match. This match will
>> correspond to a certain class and a certain range of ip addresses within
>> the
>> pool.
>>
>> The part I don't understand is : Two users are on VLAN X for instance, I
>> want to give each an ip address from a different range. I create two
>> different classes each corresponding to a different range of ip addresses
>> and to two different relay-information. Does the relay-information match
>> the
>> client-id?How is the client associated with a class?
>>
>>
>> An example taken from DOC CD:
>>
>> Defines the DHCP classes and relay information patterns
>>
>> ip dhcp class CLASS1
>>
>> relay agent information
>>
>> relay-information hex 01030a0b0c02050000000123
>>
>> relay-information hex 01030a0b0c02*
>>
>> relay-information hex 01030a0b0c02050000000000 bitmask
>> 0000000000000000000000FF
>>
>>
>> ip dhcp class CLASS2
>>
>> relay agent information
>>
>> relay-information hex 01040102030402020102
>>
>> relay-information hex 01040101030402020102
>>
>>
>> ip dhcp class CLASS3
>>
>> relay agent information
>>
>>
>> ! Associates the DHCP pool with DHCP classes
>>
>> ip dhcp pool ABC
>>
>> network 10.0.20.0 255.255.255.0
>>
>> class CLASS1
>>
>> address range 10.0.20.1 10.0.20.100
>>
>> class CLASS2
>>
>> address range 10.0.20.101 10.0.20.200
>>
>> class CLASS3
>>
>> address range 10.0.20.201 10.0.20.254
>>
>>
>>
>> Thank You
>>
>> Best Regards,
>>
>>
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>>
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>>
>>
>>
>>
>>
>>
>
>
> --
> Andrew Lee Lissitz
> all.from.nj_at_gmail.com
>

-- 
KJ
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