Re: Debian installer dhcp problems
On Thu, 29 Sep 2011 13:39:06 -0600, Bob Proulx wrote:
> Camaleón wrote:
>> Niklas Jakobsson wrote:
>> > I found this post to the dhcp-users mailing list:
>> > https://lists.isc.org/pipermail/dhcp-users/2011-July/013440.html
>>
>> W-o-w... that's incredible.
>> So it is not working even in the upstream dhcpd? :-o
>
> It may be unintuitive but ignoring client identifier is incorrect. That
> is why patching to do so isn't accepted upstream. Ignoring client
> identifier violates the protocol. See RFC 2131.
Yes, I guess that's what man page also warns about, so what's the point
in adding a setting that in the end cannot be honored? :-?
***
The duplicates flag tells the DHCP server that if a request is received
from a client that matches the MAC address of a host declaration, any
other leases matching that MAC address should be discarded by the
server, even if the UID is not the same. This is a violation of the
DHCP protocol, but can prevent clients whose client identifiers change
regularly from holding many leases at the same time. By default,
duplicates are allowed.
***
I mean, the patch is aimed to solve something that is currently there but
is not working or did I miss something?
> Now that doesn't mean that in restricted cases it isn't beneficial to
> violate some protocols. I violate protocols! (I want that tshirt by
> the way. :-)
Maybe at "thinkgeek.com"? ;-)
> Expecially when it suits me. But it does prevent it from
> being general purpose and certainly should not be the default.
If I read the man page correctly, it certainly is not the default but the
option is available for specific sitations.
> A typical suggestion for people provisioning a large number of systems
> would be to identify PXE clients using vendor-class-identifier and
> assign those a short lease time so that those addresses expire quickly
> to keep from depleting the pool.
I agree there has to be a better/another way to get the job done.
>> > It adds a new option ignore-client-uids to dhcpd. I applied the patch
>> > and recompiled my dhcp-server and it works exactly as intended.
>> >
>> > So, my problem is solved...
>>
>> Good to know, and thanks for posting the above URI and confirming the
>> patch works. What scares me is to see no replies to the user who posted
>> the message on the dhcpd mailing list...
>
> Search for Yedidyah Bar-David (aka Didi) single lease dhcp patch and you
> should get to various discussions going back several years. This isn't
> a new topic. It comes up periodically concerning booting multiple
> different operating systems and having each system assigned its own
> address.
Hum... I was not aware this was part of that well-know-discussed issues,
but regardless its "awareness status", is something that should addressed
at dhcp mailing list. I think is a valid concern for users and they
deserve a proper response, whatever it be.
Greetings,
--
Camaleón
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