Re: [exim] First time SMTP connection with "temporary error"…

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Author: Peter Rindfuss
Date:  
To: exim-users
Subject: Re: [exim] First time SMTP connection with "temporary error" to reduce spams
Heron wrote:
> Hi,
>
> I have pointed out that some SMTP servers in the world reject incoming
> e-mails for the first time with a "temporary error" message. If the message
> comes second time it is accepted.
> This mechanism is used to reject many spams, since many spam sending
> computers do not try to send the message again after receiving "temporary
> error" message from the remote SMTP server.
>
> My question is - how to implement such mechanism in Exim 4.x ?
>
>


Hi Robert,

The keyword for this technique is "greylisting" / "graylisting". Take a
look at http://www.greylisting.org/

Peter