Re: [exim] Sender callout verification with warning only

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Author: Phil \(Medway Hosting\)
Date:  
To: Exim Users List
Subject: Re: [exim] Sender callout verification with warning only

----- Original Message -----
From: "Toralf Lund" <toralf@???>
To: "Exim Mailing List" <exim-users@???>
Sent: Friday, July 06, 2007 10:59 AM
Subject: Re: [exim] Sender callout verification with warning only


>
> >
> > Do you realise that callouts are considered abusive in anti-spam circles

and
> > are often used in certain forms of ddos attacks ? Some major mail

servers
> > even BLOCK based on the number of callouts they receive from a given IP.
> > Something like 80% of emails are spam, so 80% of your callouts are being
> > directed at totally innocent machines. Challenge response methods should

be
> > considered in the same way.
> >
> I tend to consider them as a way of reducing spam, and everything that
> does is for the Greater Good, IMO. Also, I'm quite happy to receive this
> kind of requests at our server, so I'll happily use them myself -
> according to some principle we read in some holy book or the other at
> school...


You obviously haven't received 100,000+ or more of them in one day because
some spammer was forging the FROM from a domain that host. NO it is NOT for
the greater good, and would block only a tiny %age of spam. Firewalling the
entire world would also be good for blocking spam - doesn't mean its a good
idea. Try reading some of the articles on
http://www.google.co.uk/search?hl=en&safe=off&q=callouts+abusive+behaviour+spam&meta= -
especially the ones on NANAE

Taking the attitude of "it doesn't hurt me and sod the rest of the world" is
akin to "my machine has a virus but it still works fine - why should I
worry".

All the best

Phil


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