Fwd: OMAPI Host Object and Duplicate MACs in different subnets

[Caciano Machado]

Thank you Uwe,

But this solution implies in some limitations to my system. I need to
permit the addition of different DHCP configurations for each IP and
this is not possible with this approach.

The problem is a DHCP limitation for OMAPI. When I create multiple
host entries with the same hw address directly into dhcp configuration
files then DHCP server behaves well. It distributes the IPs according
to the origin subnet of the DHCP request. After my modifications DHCP
also behaves like I want using OMAPI, but only after a restart.

Anyone has a tip to help me find out a way to enable the online update
of these host entries in DHCP configuration via OMAPI?

Regards,
Caciano

On Fri, Jul 25, 2008 at 4:48 AM,  <Uwe.Buchwitz at gavi.de> wrote:
> Hi Caciano,
> if you are familiar with Perl, Just use omapi-perl.
> Adding an Host Object you can concatinate IP Adresses using a dot as
> delimiter like:
>
> $H1 = $C->Create_Host ({
>    'name'                             => 'somehost.somedomain.com'
> ,      'ip-address'            => '192.168.254.12.192.168.255.12'
> ,   'hardware-address' =>              '00:b0:54:9d:46:31'
> });
>
> The Object will then appear in the leases file with a komma as delimiter:
>
> host somehost.somedomain.com {
>  dynamic;
>  hardware ethernet 00:b0:54:9d:46:31;
>  fixed-address 192.168.254.12,192.168.255.12;
> }
>
> You can retrieve the modul from:
>
> http://www.net.cmu.edu/netreg/omapi.tar.gz
>
> regards
>
> Uwe
>
>
>
>
>
>
>
> "Caciano Machado" <caciano at gmail.com>
> Gesendet von: dhcp-hackers-bounce at isc.org
> 24.07.2008 22:19
> Bitte antworten an
> dhcp-hackers at isc.org
>
>
> An
> dhcp-hackers at isc.org
> Kopie
>
> Thema
> Fwd: OMAPI Host Object and Duplicate MACs in different subnets
>
>
>
>
>
>
> Hi,
> I'm managing to enable duplicate MACs in different subnets for ISC
> DHCP with OMAPI host entries. After some workarounds I've got some
> progress. Here is a patch (for dhcp 3.1.1) with the modifications I've
> done. With this, I can add more than one IP for each MAC. I just
> removed some tests that were avoiding the duplication and I don't know
> what are the side effects :-). Although, the host entries are
> activated only after a DHCP restart. How can I enable the "online"
> activation of these entries? Any suggestions?
>
> Regards,
> Caciano
>
> ---------- Forwarded message ----------
> From: Simon Hobson <dhcp1 at thehobsons.co.uk>
> Date: Wed, Jul 9, 2008 at 3:48 AM
> Subject: Re: OMAPI Host Object and Duplicate MACs in different subnets
> To: dhcp-users at isc.org
>
>
> At 17:38 +0200 8/7/08, Stéphane PURNELLE wrote:
>>
>> It's possible to have multiple same MAC address ?
>
> Officially no, in practice yes.
>
> Every MAC address is supposed to be unique - manufacturers are
> supposed to obtain one (or more depending on quantity) 3 byte prefix
> from the registry, and are then supposed to track which combination of
> the last 3 bytes they have used.
>
> In practice there are a number of problems :
>
> 'cheap' manufacturers who don't (or didn't) grasp the importance of
> this and so just made up some numbers
>
> 'not quite so cheap' manufacturers who bothered to get a prefix, but
> then didn't track what they've used
>
> 'cock ups' that can happen to even the biggest of manufacturers. I
> heard that for a while, Dell were duplicating one value in every 257
> machines shipped (ie of the 256 values for the last byte, one got used
> twice).
>
> 'helpful' users or admins that reprogram a card to match what they just
> took out
>
>
>
> In small networks it doesn't matter as the chances of getting a
> duplicate are slim. But as the network gets bigger, the chances of
> having a problem go up. Some (like the Dell problem) only show up if
> you buy a lot of machines at the same time - like a local university
> with a large flat network and did an update by buying thousands of
> machines in one order (I know one of the admins and they were 'a bit
> puzzled' before they figured out the problem !)
>
>
>
>
>
>