Duplicate lease, different ip.

Douglas Power dpower at fnb.co.za
Thu May 3 05:16:18 UTC 2007


I have applied the patch from <http://www.cs.tau.ac.il/~didi/dhcp/> to
V3.1.0a3 and this fixes the duplicate but I am unable to start the
service through init.d as it gives me a usage error:

Internet Systems Consortium DHCP Server V3.1.0a3
Copyright 2004-2007 Internet Systems Consortium.
All rights reserved.
Usage: dhcpd [-p <UDP port #>] [-d] [-f]
             [-cf config-file] [-lf lease-file]
                   [-tf trace-output-file]
                   [-play trace-input-file]
             [-t] [-T] [-s server] [if0 [...ifN]]

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It works fine if I start it manually without the -chroot option which I
am not happy about as it isn't secure enough. I will let you know if I
can figure this out. If you have any suggestions they would be greatly



On Wed, 2007-05-02 at 14:28 -0700, David W. Hankins wrote:
> On Mon, Apr 30, 2007 at 12:11:18PM -0300, Bruce Hudson wrote:
> >     However, the first time the server see a request with an identifier it
> > will "upgrade" an existing lease for that client address that does not have
> > one by adding it. The process is not reversible so any requests there-after
> > without an idetifier are a different client. There was an ancient message
> > to the list from Ted Lemon that called this "tragically unavoidable". 
> This is only true IFF you are running an older version of the software
> (with a bug) and the client that has a uid and identical chaddr has
> "requested" the old address.  New versions will never 'upgrade' a
> lease from chaddr-identified to client-identified.
> That does not help someone who is using PXE because ping-before-offer
> will successfully ping the PXE client, and abandon its lease, so even
> the old software won't work.
> I'm not sure it's unavoidable.  But it's "working as intended" that
> these two clients get different leases.  This was Ted's interpretation
> of RFC2131, and I share it.
> It's certainly tragic.
> I wanted to get a feature into 3.1.0 that would help administrators
> sort client identification problems out using config syntax (with an
> eye towards the future which is RFC4361).  We cut 3.1.0 to alpha
> before I could start on that feature.
> I don't remember if didi wrote a second patch, but the one I
> remember disabled the client-identifier entirely...this is not
> something we feel we can incorporate in the official software.
Douglas Power <dpower at fnb.co.za>

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