Reverse DNS lookup - how to stop spam with Exchange 2003

Posted on 2006-05-26
Last Modified: 2008-01-09

I have read multiple questions on EE regarding this, none of them answer my question - how do I use reverse DNS lookup to block spam emails? I realise that the 'use reverse DNS lookup on incoming messages' checkbox in SMTP properties just adds the resolved name to the header, what I am looking for is a way to block emails on the basis of reverse DNS lookups, much like AOL do. Is it an Exchange setting?
Question by:5t34lth_G33k
    LVL 6

    Assisted Solution

    I believe your refering to something called SPF (Sender Policy Framework,) in whch the recieving server does a reverse DNS lookup to verify the identity of the sending server.  I do not believe this is part of exchange.

    I would not say this is standard practice just yet so you could lose e-mails from people sending you mail whose servers do not yet have the reverse DNS record added yet.
    LVL 15

    Expert Comment

    Here is some more information about SPF


    LVL 104

    Accepted Solution

    The perform reverse DNS lookup option that is built in to Exchange is close to useless. It doesn't actually block anything, just carries out the test.
    You will need to use a third party tool to actually block the application, or a RBL.
    Personally, I am having some success with Vamsoft ORF. It is priced per server and sits in front of the Exchange server.

    SPF is also useless on its own. The deployment isn't wide enough to actually make use of it, so the most you can do is use it along side something else to score the message as being spam (or not).

    IMF does quite a good job with some sites. You can enable it without actually getting the product to do anything, just scan. Then use perfmon to monitor what it is doing.

    LVL 7

    Author Comment

    thanks to all for their input - its a shame take-up on SPF isn't widespread, as that could potentially solve all our problems. We cannot risk losing 'real' emails, however, so this will have to wait.


    Featured Post

    Do email signature updates give you a headache?

    Do you feel like all of your time is spent managing email signatures? Too busy to visit every user’s desk to make updates? Want high-quality HTML signatures on all devices, including on mobiles and Macs? Then, let Exclaimer solve all your email signature problems today!

    Join & Write a Comment

    Learn more about how the humble email signature can be used as more than just an electronic business card. When used correctly, a signature can easily be tailored for different purposes by different departments within an organization.
    Find out how to use dynamic social media in email signatures with this top 10 DOs & DON’Ts.
    In this video we show how to create a Resource Mailbox in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: Navigate to the Recipients >> Resources tab.: "Recipients" is our default selection …
    In this video we show how to create a mailbox database in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Servers >> Data…

    728 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    20 Experts available now in Live!

    Get 1:1 Help Now