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No Effective Spam Solution?

Discussion in 'Plesk for Linux - 8.x and Older' started by consultant, Jun 30, 2006.

  1. consultant

    consultant Guest

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    I've personally found the challenge-response third party spam filters to be by far the most effective. I realize the selfish aspect of using one of these services as they multiply the amount of undelierable e-mail floating around with all the auto-repsonse challenge message.

    So I'm working with a company of 20 employees that wants to reduce their spam. We installed SpamAssassin on their server (Pleask 7.5 Reloaded.) It hasn't identified a single spam message. The reason is all the spammers know exactly how to craft the e-mail to avoid the filter. Many of the e-mails that get through are just an image file with the text in it. Other's are plain text messages where any trigger words are intentionally misspelled. It appears these content-based filters like SpamAssassin or the 4PSA product are more or less useless from the aspect of providing any *significant* amount of SPAM reduction. Maybe they'll catch a message or two here and there but in large part, the spammers are way ahead of these guys. So that leads back to challenge-response really being the only *significantly* effective solution. It gets ALL my spam, and maybe 1 in 25 legitimate senders are too stupid, paranoid, or lazy to respond to the challenge so I periodically scan the junk folder and whitelist them.

    If you count out the Challenge-Response method of SPAM filtering, the only other effective option is to simply change your e-mail address periodically and be careful what forms you put it on. I have several "disposable" addresses I use when I suspect I could end up on a list.

    Is Challenge-Response really so bad? Is there a content-filter based SPAM solution out there that REALLY works and if so what is the typical percentage of SPAM it is currently catching on your server?
     
  2. Galactic Zero

    Galactic Zero Guest

    0
     
    Have you looked at adding Rules du Jour? I've been running that and so far it has caught 98% of the spam. If you haven't yet looked at AtomicRocketTurtles.com website at the anti virus/spam section you probably need to.

    My current setup is RHEL 3, PSA 7.5.3, Spamassassin from ART's repo, ClamAv from Dag's repo, psa-spamassassin 7.5.4, Pyzor, Rule du Jour with these filters, portion of my mail header follows:

    X-Spam-Flag: YES
    X-Spam-Checker-Version: SpamAssassin 3.1.1 (2006-03-10) on gz.galacticzero.net
    X-Spam-Level: *************************
    X-Spam-Status: Yes, score=25.3 required=7.0 tests=BAYES_80,
    RCVD_IN_BL_SPAMCOP_NET,RCVD_IN_DSBL,RCVD_IN_NJABL_PROXY,
    RCVD_IN_SORBS_SOCKS,RCVD_IN_SORBS_WEB,RCVD_IN_XBL,UNPARSEABLE_RELAY,
    URIBL_JP_SURBL,URIBL_OB_SURBL,URIBL_SBL,URIBL_WS_SURBL autolearn=spam
    version=3.1.1
     
  3. atomicturtle

    atomicturtle Golden Pleskian

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    Theres certainly no silver bullet in anti-spam systems. Personally, email challenge-response systems evoke a level of vitriolic hatred on my part that I can only compare to the disgust I feel toward alpacas, or the fat kid on season 2 of "CHiPs".

    You either love it or hate it, I suppose. Then I think you go around trying to convince other people to love it or hate it.
     
  4. sieb@

    sieb@ Guest

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    I use a seperate server on the frontend to filter all the spam before it gets to the hosting servers. Its MailScanner with MailWatch, MailScannter-MRTG, and BitDefender scanner. It gets 70-90% depending on how many total messages come through that day. Fort Systems has a mailscanner (same setup but with their own web frontend) that I used with much success before I built this. This lightens the load on my hosting servers and lets the users set stricter spam settings if they like.
     
  5. atomicturtle

    atomicturtle Golden Pleskian

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