what is DoubleCheck?

Sven sven@dmv.com
Tue Jul 8 13:02:11 UTC 2003

Vernon Schryver wrote:
> While checking DCC clients sending excessive numbers of DCC NOPs to
> the public DCC servers that something called "DoubleCheck" involves
> a DCC client.  Does anyone know anything about it?
> I found http://www.nmgi.com/doublecheck/index.shtml
> but learned little from it.

Digging about their site a little I found more information about the
doublecheck filtering appliance
(http://www.nmgi.com/doublecheck/spam.shtml). From the provided screenshots
it would appear that it relies on SpamAssassin which does now include DCC
checks in its arsenal of tools. I am not sure where the NOPS come into play
(are those just to test the availibility and RTTs of the servers?).

> As I've said before, selling the services provided by others does not
> seem ethical.
We actually ran into this issue back when we used Vipul's razor. Although
the Unix version was deemed "free", once we started blasting their servers
with our volume of email, they quickly contacted us about paying them for
the service. As such, I don't think we could get by using spamassassin with
the razor checks enabled without coughing up $x per mailbox. Because DCC
allowed us to host our own servers (versus Razor's closed system) and the
inexpensive cost (currently the bandwidth used by our newly installed public
server) it was an easy move to this effective system.

I would agree that reselling this service as provided exclusively by public
services (as opposed to running ones own internal DCC servers and querying
those) does not seem ethical. How to distinguish between those using public
servers as a value-added service, as a personal service by the end-user, or
as a commercial venture in and of itself becomes a bit of a gray area. It
would be interesting to see if some distinction could be made and some fee
system put in place for the purely commercial venture system (such as
doublecheck would appear to be).


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