Re: DHCP

From: Jeigh (folkens.jason_at_acd.net)
Date: 09/17/04 

Date: Fri, 17 Sep 2004 09:58:06 -0400

Thanks for the response, irwiin...

I understand what you mean, but go one step further.

Does the router change the contents of the DHCPDiscover packet, inserting
the subnet information into the bootp packet, when it passes it through the
router (when bootp is routed)?

dhcpdiscover packets don't know what subnet they are on.... so how does
the dhcp server know with which scope the server should lease the new IP
from?

"Irwin Utama" <irwin_utama@yahoo.com> wrote in message
news:uiR%23y$HnEHA.748@TK2MSFTNGP15.phx.gbl...
> Hi Jeigh,
>
> DHCP uses broadcast to send its packet. So it is only limited to its own
> subnet, that's why we need to set up dhcp relay agent on other subnet to
> pass the packet to the DHCP server. DHCP relay agent will forward packet
> from client to the DHCP server that listed on it. DHCP will assign IP
> address to the client based on subnet of its dhcp relay agent.
> If you use dhcp relay agent, you donot need to pass bootp packets on your
> router.
>
> regards,
> irwin
>
>
>
> "Jeigh" <folkens.jason@acd.net> wrote in message
> news:ReCdnQy8yOW9_dfcRVn-rQ@giganews.com...
>> I'm confused.
>>
>>
>> Heres my situation...
>>
>> I have 1 DHCP Server with two scopes.
>> The dhcp server is 192.168.1.2.
>>
>> The first scope handles 192.168.1.x
>> The second scope handles 192.168.2.x
>>
>> The subnets are connected through a router that passes bootp through
> it....
>> In a seperate implementation, there may be a dhcp relay agent, but since
>> there are no significant configuration options set when installing a dhcp
>> relay agent, I don't think that changes the answer to this quesiton so
> lets
>> pretend that the router passes bootp traffic to the subnet with the DHCP
>> server.
>>
>> How does the DHCP server determine which subnet a dhcp client is on,
>> prior
>> to the server giving the client its new IP. In a routed network, where
>> there are multiple scopes, different dhcp options must be set up for each
>> individual scope, and each scope is used to set options for all dhcp
> clients
>> on a given subnet... but how does DHCP know which subnet a specific
> client
>> is coming from unless it already has an IP address?
>>
>> I've read documentation stating that in a multihomed DHCP server setup,
> the
>> DHCP server actually needs to have a seperate nic to be associated with
> each
>> individual scope... but I cant believe that that is the case in this
>> situation because if that were true, then DHCP Relay agent would have a
> very
>> limited purpose, and bootp would never be routed.
>>
>> any ideas?
>>
>> -- Jason
>>
>>
>
>

Relevant Pages

  • Re: DHCP adres in superscope
    ... A superscope is an administrative grouping of scopes that is used to support ... Before passing a DHCP message on to a DHCP server, ... message informs the DHCP server of the subnet ID of the originating subnet ...
    (microsoft.public.cert.exam.mcse)
  • Re: DHCP relay, superscope and laptops
    ... each of which has it's own subnet. ... The Switch then acts as a DHCP relay, ... relaying DHCP requests to a central DHCP server, ... What we did as a workaround, was that we created one superscope for each ...
    (microsoft.public.windows.server.networking)
  • Re: DHCP problem
    ... I agree with all your points but have inherited the network the way it is ... I've tried giving a NIC 2 IP addresses and then have it give out DHCP ... I think I'll try harder to convince everyone involved that a single subnet ... >> different subnets....ideally from a single DHCP server. ...
    (microsoft.public.windows.server.general)
  • Re: wireless router off a normal router
    ... > seem that a router running DHCP and NAT services has essentially ... I think the issue is obscured by the fact that many boxes are both NAT ... The NAT router defines the range of the subnet. ... So if you'd have a second DHCP server active on that same subnet, ...
    (comp.sys.mac.comm)
  • Re: DHCP serving more than one subnet (longish)
    ... > packets to allow a host's ethernet layer to pass the packet onto the TCPIP stack. ... DHCP packets are formatted the same as any other IP packet. ... > address nor that of a DHCP server. ...
    (comp.os.vms)
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