15th 2006f September, 2006

Greylist – a free grey list for Exchange.

by @ 3:29. Filed under Programming, Projects
I know – I know – I know. Programs don’t really fit into Grynx’s profile – but hey – I make’ed something and now I’m sharing it with you. It might not interest you that much if you’re not an Exchange admin or have an Exchange server, but that’s just the way things are.

Greylist is simply a greylist program for Exchange 2003 ( should work on 2000 ) which will delay incoming mail for a couple of minutes. In my environment it blocks 98% of all spam and so far it hasn’t blocked a single ‘good’ email.
And as I like the whole idea of open source, I’m publishing it just like that – for free. Or rather freeware.

I wrote this as I couldn’t find any free grey list programs out there. Lots and lots for free for Linux, but only commercial products for Exchange.

Link: Greylist v1.0 for Exchange

7 Responses to “Greylist – a free grey list for Exchange.”

  1. Heywood J. Blaume Says:

    This thing is fantastic. I was struggling with configuring an upstream Postfix-based greylisting SMTP server for my small Exchange server environment, but I found this and it works exactly as advertised. Thanks so much for your contribution.

  2. Loris Says:

    Hi Chris,

    Great piece of software. The only problem with it: it doesn’t run
    as smooth as it could on non-US locales. The admin returns:
    Syntax error in date in query expression ‘#22.11.2006#’ (swiss locale).

    Hope you can fix this. I would love to take this productive.


  3. Mike Verheul Says:


    Seems to work like a charm.
    Only thing is that the ‘disconnect’ message on internet is “451 Requested action aborted: local error in processing” and not the message as said in the readme.

    But works like a charm! Thanks

  4. Chris J. Says:

    Mike: The wording doesn’t really matter as the piece that matters is the 451. This is what the sending mail server uses to determine the error.

  5. Uttang Dawda Says:

    Perfect . A impressive peice of code.
    I was wondering if this worked with Exchange 5.5(my company is on a tight budget).
    Thanks NEways will surely contribute towards this site ( My pocket isnt so small as my company:D)

  6. Chris J Says:

    Hi there. I do not get the 451 code that is needed to let the sending server know that it is “delayed”. I get a very snappy disconnect.

  7. Enrique Q Says:

    Great little application! Very effective implementation of a simple concept. Currently testing on 5 different Exchange servers and no complaints, if no major issues arise in the next two weeks, expect five registrations for your product.

    Many thanks,

    P.S. Chris J., please troubleshoot your own server…

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