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Article Questions - Filtering E-mail by World Regions in Exchange Server 2003

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  • Article Questions - Filtering E-mail by World Regions in Exchange Server 2003

    We have been using the following article from this website to provide country code filtering the the Exchange boxes we manage:

    http://www.petri.com/filtering-email...erver-2003.htm

    It has worked well in filtering emails by country code. However, in one instance, we found that it failed for a user. Country codes we had configured on the server got through to this user even though we had the filtering set up correctly. We are using the second part of the article for our customer's configuration.

    What I'm curious about is whether or not this configuration fails if the Exchange server cannot contact the domain that provided in the instructions and by default, lets the email through. I would also like to hear if there are any other caveats to this configuration that we should be aware of.

    Thank you for your time and I apologize in advanced if this has been covered before as I performed a search and didn't find what I was looking for.

  • #2
    Re: Article Questions - Filtering E-mail by World Regions in Exchange Server 2003

    There are always issues with doing any kind of blocking using blacklists. I personally don't use them as I don't like the idea of someone else deciding what email I receive. Block by country can work if you know 100% that you will never get email from those locations, but the benefits in my mind are limited due to the fact that most spam originates from the USA.

    If the blacklist lookup fails for some reason then the messages will come straight through. If you are having DNS issues then you might want to switch to something like OpenDNS which is ISP independent.

    Simon.
    --
    Simon Butler
    Exchange MVP

    Blog: http://blog.sembee.co.uk/
    More Exchange Content: http://exchange.sembee.info/
    Exchange Resources List: http://exbpa.com/
    In the UK? Hire me: http://www.sembee.co.uk/

    Sembee is a registered trademark, used here with permission.

    Comment


    • #3
      Re: Article Questions - Filtering E-mail by World Regions in Exchange Server 2003

      Thank you for the reply and I apologize for the response being untimely.

      I kind of figured that much but at the same time, wanted another opinion on the matter. This is the situation I'm presented with:

      Our customers are getting hit with backskatter spam. Spammer sends out his spam using the source email address as one of our customers addresses. Whatever spam doesn't get through, gets sent back to the customer as NDR's. We require the NDR's be enabled so that we will know if legitimate email is being bounced back but at the same time, we need to be able to eliminate the NDR spamming we receiving during one of these spam bombs.

      I'm open to any suggestions.

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      • #4
        Re: Article Questions - Filtering E-mail by World Regions in Exchange Server 2003

        You can't really do a great deal about backscatter spam, because if you try and block NDRs being delivered to your server you will get blacklisted yourself.

        If you are being spoofed then you need to look for a product that can deal with the backscatter NDRs for you. However these messages would be dropped after delivery, not during.

        Simon.
        --
        Simon Butler
        Exchange MVP

        Blog: http://blog.sembee.co.uk/
        More Exchange Content: http://exchange.sembee.info/
        Exchange Resources List: http://exbpa.com/
        In the UK? Hire me: http://www.sembee.co.uk/

        Sembee is a registered trademark, used here with permission.

        Comment

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