Stupid "duplicate" question

David W. Hankins David_Hankins at
Mon Jun 25 21:07:26 UTC 2007

On Thu, Jun 21, 2007 at 09:34:38AM -0400, Brent L. Bates wrote:
>      How about stupid email list software?  I didn't send a blank message.  It
> didn't have any attachments either.  However, the email list software deleted
> the entire body of my message.

I've been told it will be replaced soon, but it is possible that was
a tease.

>      Just another data point.  We occasionally get the same message in our
> logs.  I don't know what they mean and I just ignore them.  We don't get that
> many of them, but we don't have that many DHCP clients either.  They seem to
> happen to the same MAC addresses.  Looking up the MAC addresses of some of
> these and 2 are MacTrashes and one was some kind of Sony device.

It's "probably" cosmetic, and if it isn't, then it's just
'informational'.  The server has dealt with the problem so none
should remain.

Basically what's happening here is the client (for some reason) has
more than one lease in its database that matches the client's identity.

That's all.

When the "duplicate" lease is also ACTIVE, and the client is binding
to another address ("DHCPREQUEST"), we also release the old lease.

But that log message is printed out either way, so it's possible (if
not probable) that the server isn't actually taking any special
action when you see it.

We're going to silence the log message unless some action is really
taken by the server.  We'll probably make a new log mesasge that
makes it clear what changes the server is making.

As for limiting the number of times that a client does have more
than one address with its identifiers attached to it in the database,
the latest versions (4.0.0, 3.1.0, 3.0.6) all contain a change that
sorts the by-identifier hash bucket contents, which has the effect
that it encourages reuse of ACTIVE leases rather than handing out
FREE or BACKUP leases that have the client's old identity on them.

We haven't yet engineered changes that reduce the number of leases
to 1 reliably, such as by dealing with the PXE/WinCE or similar

Ash bugud-gul durbatuluk agh burzum-ishi krimpatul.
David W. Hankins	"If you don't do it right the first time,
Software Engineer		     you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins

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