Greylisting (WAS: gif attachments)

Dennis Willson taz at
Wed Aug 23 22:24:37 IST 2006

Additionally, I have a problem with "legitmate SMTP server" and not 
respecting the "try again later". There are lots of reasons a mail 
server may return a temp error other than greylisting. Like too high 
of a load (currently under a Spam attack), too many connections, 
etc... If you really want your email delivered you pretty much have to 
honor the temp errors and try again later. 

On Wed, 23 Aug 2006 17:02:06 -0400
  "Daniel Maher" <daniel.maher at> wrote:
>> -----Original Message-----
>> From: mailscanner-bounces at 
>> bounces at] On Behalf Of Julian Field
>> Sent: August 23, 2006 4:29 PM
>> To: MailScanner discussion
>> Subject: Re: gif attachments
>> Try implementing greylisting on your servers. This has helped a lot 
>> this problem on my systems.
>> Even if you set the greylisting delay as low as 5 minutes.
>My big fear w/ Greylisting is that a (legitmate) SMTP server 
>somewhere won't respect the "try again later" code, and instead just 
>fail to deliver the mail.  I've heard rumours that some of the larger 
>webmail providers exhibit this behaviour.
>   _
>  °v°  Daniel Maher
>/(_)\ Administrateur Système Unix
>  ^ ^  Unix System Administrator
>Sentio aliquos togatos contra me conspirare.
>MailScanner mailing list
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>Before posting, read
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Dennis Willson

taz at

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