[Mimedefang] Re: Filtering idea for stock pump&dumps

[Kevin A. McGrail]

>> FYI, based on what we have confirmed over the past 2 weeks, greylisting 
>> is
>> causing widespread FPs with Microsoft Exchange 2003 SP2.  In short,
>> Microsoft is interpreting 4XX errors as 5XX errors and generating NDRs.
>
> If broken mailers receive responses that they (and their users) don't
> expect, then perhaps that will be an incentive to fix them, or to stop
> using them.  I don't much care either way.

I can't name a mailer that isn't broken in some way or another.  The RFCs 
just aren't specific enough to allow for anyone to claim 100% compliance not 
to mention there are some stupid things that just aren't used or are likely 
to cause security concerns.  The reality is that there are a lot of SMTP 
daemons and they all have to play nice with each other to a certain extent.

Ignoring the bugs in one mailer daemon is worthless banter to me.  I live in 
a reality where I need email to flow constantly and consistently.

> FWIW I've never seen one of these messages.  I haven't done anything
> specifically to prevent them getting through.

You wouldn't see the message unless you run a Microsoft Exchange Server and 
you are having troubles sending to a host that has greylisting implemented.

> Those of you who can
> remember my somewhat uncompromising approach to mail filtering might
> not be surprised by that; those that don't might want to take a look
> at the List archives - I'm not a prolific poster - or maybe at
>
> http://www.ii.com/internet/robots/procmail/qs/#spam.
>
> Yes, I still get a few false positives.  I'd much rather deal with
> those than with tens of thousands of false negatives, just one of
> which (together with a little human frailty) cost a friend of mine
> fifteen hundred dollars.

I don't have the luxury of interfering with emails and I feel the exact 
opposite where a single FP is 1000x worse than a single SPAM.  Though I am 
sorry about your friend and work very hard most every day blocking these 
bastards.

Regards,
KAM