bad DCC traffic from

Jon Webb
Mon Sep 2 15:47:03 UTC 2002

It's quite possible that I made a mistake in this new software, which is
causing problems. I apologize for that, and I would appreciate being given a
chance to fix the bug.

So please, let me look into the problem, before labelling my code as
"abusive". If you have any information that would help me track down the
bug, I'd appreciate hearing it.

I don't think the suggested problem is the real issue--while I don't use the
shared map file, I do retain it's contents in memory for the duration of an
Outlook session--or at least, I think I do. (I'll check this, of course.) If
the software is working the way I think it should, the transactions Vernon
mentions should occur at the beginning of each Outlook session, and then
again whenever they would normally occur in DCC. So I don't think this
should cause the problem you are seeing.

It is, of course, possible that there's a bug, and the transactions are
occurring much more often than that. It's also possible that the
transactions are simply due to a much larger number of DCC clients; after
all, with the PC software each PC becomes a DCC client (which I know is not
as good a design as having the mail servers be the clients, but many people
can't control their mail servers.)

Let me look into the problem and see if I can figure something out. In the
meantime, I would appreciate your patience.

Jon Webb

-----Original Message-----
From: []On Behalf Of
Vernon Schryver
Sent: Monday, September 02, 2002 10:48 AM
Subject: bad DCC traffic from

Does anyone know anything about or
Goodbytes Information Products Inc

I am seeing DCC traffic from or
that could be considered abusive.  It consists only of zillions of DCC
NOP operations.

There are some other hosts that do almost as much.

I wonder if the cause might be the recently advertised PC code.  I
suspect that code lacks the shared map file containing RTTs and other
information of the proper DCC design, and as a consequence, every
operation involves a round of RTT measuring.  The result of that is
currently a 6 fold increase in the load imposed on the public DCC
servers by that software compared to a proper design.  When more public
DCC servers are available, the problem will be worse.

What countermeasures are appropriate?

Vernon Schryver
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