spam statistics. Commercial software Sophos v Spam Assassin.

Discussion in 'NZ Computing' started by thing, Mar 9, 2005.

  1. thing

    thing Guest

    Our old system is Spam Assassin, new is Sophos

    A sample of tagging correctly over the last 8 days,

    64% - Average

    Spam A
    75% - Average

    I am sort of perplexed, Sophos is updated every hour automatically, Spam
    Assassin 2 or 3 times a week manually....

    Ever since we put the new system in Spam Assassin seems to be
    consistantly beating it (Sophos)......yet Sophos is costing us an arm
    and a leg.....

    Is there anybody else who has experienced this sort of thing? Is there
    anything that could be skewing the statistics unfairly?


    thing, Mar 9, 2005
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  2. thing

    Steve Guest

    What platform are you using? Sendmail?

    Steve, Mar 9, 2005
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  3. thing

    Tim Guest

    Your statistics could be misleading you since you appear to be averaging a
    percentage. Return to the base data and draw the end percentage directly
    from that. I would show the message counts and 'hits' followed by %, then
    sum the counts and hits then show then newly calculated %.

    The top list may have had 81% of a very large volume on one day, but because
    the volume does not come into the end result its significance may be lost
    statistically. It could just as easily be a very quiet day and the products
    are as you observe...

    - Tim
    Tim, Mar 9, 2005
  4. I've seen that(paid for product sucks) here at work where mailmarshal is
    crap at finding spam until you wind it up to "Im not going to let
    anything through" mode, at which point it catches too much legit mail to
    be useful, and so it remains letting a fair bitthrough, although getting
    less as I refine the filters.

    I havent used it(SA) in a while... does it learn yet?
    maybe it's trained itself to be better.
    Dave -, Mar 9, 2005
  5. thing

    thing Guest

    Sendmail for Sophos, postfix for Spam Assassin.


    thing, Mar 9, 2005
  6. Just for info
    8300 blocked spam
    250 blocked virus
    12000 legit
    ~2800 users
    so ~3 legit:2 spam

    crap... 40% thats low compared with what I've read elsewhere.
    Dave -, Mar 9, 2005
  7. thing

    Steve Guest

    If your sendmail is on linux or solaris, you might want to try this Kiwi
    product, rather than that british stuff. What do they know about *our*
    spam, eh?

    (somewhat cheaper, too!)

    Steve, Mar 9, 2005
  8. thing

    thing Guest

    Yes, Linux.

    I think we have had this discussion........

    1) I have been reading up on mailwasher, I notice the comments on the
    performance hit on the server, it is noticable, Sophos also has this
    penalty, so on the face of it, no advantage either way.

    2) The mail washer's site lacks any depth on explaining the product and
    its components or if it is there I could not find it yesterday.

    3) Like Sophos I see no evidence it is robust and scalable.

    4) Maturity, Sophos's system has been around a while.....mail washer is
    how old?

    I am trying to build up a case to dump Sophos, I would be shot if I
    installed something else as bad or worse....and I like my job....

    I also am getting very tired of being some company's software guinee
    pig......and getting a whipping as a result when it goes wrong.....


    thing, Mar 9, 2005
  9. this any help?
    Shane (aka froggy), Mar 9, 2005
  10. 50-60% correctly found spam? That seems VERY VERY low (even for
    spamassassin). Spam Assassin should give normally out of the box about 95%.

    Other products like the open source dspam
    ( will give 99.99%

    Craig Whitmore, Mar 11, 2005
  11. I think individual users can set it up to do Bayesian learning on their
    own e-mail. In its default, systemwide configuration, it doesn't do
    this. At least, not the way I have it set up.
    Lawrence D¹Oliveiro, Mar 11, 2005
  12. Maybe a similar principle applies with this as with cryptography: the
    open, public approach beats the closed, secretive one simply because the
    former can bring a wider range of minds to bear to find weaknesses and
    plug them, leading to a stronger product.
    Lawrence D'Oliveiro, Mar 11, 2005
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