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De-spamming Your Inbox The Hard Way

Posted by CmdrTaco on from the going-to-far dept.

ajain writes "Even after using precautions like dummy email address in public forums, I have been plagued by the spam mails for long time now. Accidentally, I hit upon a not-so-elegant but effective solution recently: Ever thought of shutting down the mail server temporarily to stop spam to your inbox permanently? Well, it seems to work. In my case, a two-day shutdown resulted in 97.5% decrease in spam traffic! Here are the details and a step-by-step guide to this desperate-method of spam reduction. I think I'll model, simulate and then optimize the amount of shut-down time required for spam levels to drop to zero!"

4 of 631 comments (clear)

  1. Yes, like greylisting. (ie, Postgrey for Postfix) by kriegsman · · Score: 5, Interesting

    Our Postfix mail server uses Postgrey (click link for graph showing effectiveness), and it's as close to 'magic' as I've seen yet in the antispam category.

    -Mark

  2. Or delay delivery, and check again ... by theblackdeer · · Score: 5, Interesting

    Our ISP has set up a slightly more elegant way to fliter out lots and lots of spam. They call it DoubleVerify.

    From the FAQ (http://www.olympus.net/doubleVerifyNL):

    DoubleVerify gets two chances to automatically identify mail. When mail arrives at our mail server the first time our server requests the sending mail server to send it a second time. Spammers rarely comply. Legitimate mail servers typically resend the mail about fifteen minutes later. Once OlympusNet receives mail the second time, it immediately delivers that mail and continues to immediately deliver mail from that sender. The DoubleVerify process works invisibly and is handled automatically by the mail servers.

    You can whitelist entire domains (like your company, for example), too. It's worked pretty well for us.

  3. Re:Another approach... by Anonymous Coward · · Score: 5, Interesting

    Actually if you own a domain. Simply use abuse@yourdomainhere.com as your e-mail address. You will never receive any spam. I know this is not practical for most people but it works flawlessly.

  4. Those who don't understand technology are ... by Obfuscant · · Score: 5, Interesting
    doomed to repeat it. From the article:

    During that time, all the mails sent to my mail account were of course bouncing.

    Of course they were NOT. During that time, emails sent to your account were being held at the sending server, or, in the case of spammers who aren't using open relays, there was a timeout during the connection to port 25 on your server. Neither results in a bounce. Most intelligent email systems are set up with a 5 day queue.

    In other words, it will take 5 days for bounces to start being sent. That's for real email. For the spam, the bounces will be sent to fake addresses and the spammers will never see them.

    I've had systems in place on many of my accounts for YEARS that bounce (reject with "unknown user" errors) spam and the same spammers keep sending the same shit over and over again. I've waatched the mail logs on my domain's servers where 99% of the incoming email is undeliverable spam (it ALL bounces) and the same spammers keep sending the same shit over and over again. Spammers simply either DO NOT CARE if they get a bounce, or do not see the bounces anyway.

    There must be a different explanation for the reduction in spam. A new spam filter on the server, for example. Spammers seeing bounces and stopping is patently ridiculous.