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How To Fight Spam Using Your Postfix Configuration

Posted by ryuzaki0 on from the not-welcome-here dept.

hausmasta writes, "In this guide you will learn how to tweak your virtual Postfix setup to better combat spam by stopping the mail before it hits SpamAssasin, using RBL (Realtime Blacklists) and RHBL (slightly different), greylistings, and Helo Checks." A clear, step-by-step guide to a complex subject.

2 of 158 comments (clear)

  1. Re:RBLs and not getting your mail by Philosinfinity · · Score: 4, Insightful
    If you're running the mail servers for a business, how prudent is it to run a spam filter in the first place? While using something that relies on checking the content of the mail may be useful in getting rid of the most egregious spam, you don't want to block all items identified as spam. You can't run the risk of blocking your customers.
    The firm that I work for gets something like 160,000 emails from external sources a day. Roughly 10% of these are legitimate. How prudent is it to force users to sift through 90% crap in order to get to the legitimate 10%. Currently, we use Postini as our primary MX host. They forward legitimate messages directly to our Exchange server, filter out 100% guaranteed spam, and drop the remainder into a quarantine that we check every few hours. Basically, all I am getting at is that spam filtering is necessary for enterprise environments and that there are actually some good tools to acheive it.
  2. greylisting not all that useful. by nblender · · Score: 4, Insightful
    To all you greylisters, I don't know what part of the interweb you're from but when I survey my spam, I find that great tracts of it come from zombies via their ISP's mail server which means greylisting is no longer effective. It was effective last year but I think you folks missed the boat. I moderate a mailing list for a popular open source operating system project that uses greylisting and I still get about 100 spam per day as owner-listname...

    Spammers are having their zombies dig through the windows configurations to find the owners email relay and using that to send their spam. It's not that difficult and combats greylisting.