Re: public blacklists

From: Ed Wilts (ewilts_at_ewilts.org)
Date: 12/09/04

  • Next message: HENRIQUE: "Re: firehol" 
    Date: Thu, 9 Dec 2004 12:32:47 -0600
To: For users of Fedora Core releases <fedora-list@redhat.com>

    On Thu, Dec 09, 2004 at 10:06:32PM +0800, Ow Mun Heng wrote:
    > In that case, in some cases, eg: if one runs their own mail-server,
    > grey-listing seems to be a better option compared to spamassassin, even
    > when using SURBL.
    >
    > Reason being, greylisting stops it at the MTA level, spamassassin only
    > tracks it once it's already in the system.

    greylisting doesn't stop it all. There are a bunch of well-behaved mail
    servers out there sending spam and if you don't have spamassassin or
    some such tool installed, you will get spam. I turned on greylisting
    last night on my home server and still had 10 spam messages by morning
    that spamassassin/procmail had delivered to by spam folder.

    A coworker turned on greylisting on his home system last night and
    discovered that a message from the mrtg mailing list was initially
    blocked but not retried. In other words, a legitimate message that
    should have been delivered went to the bit bucket. You can make a
    perfectly valid case that the server that tried to deliver it is broken,
    but you can also make a perfectly valid case that you're now preventing
    legitimate e-mail from being delivered. Yes, you can add specific hosts
    to a whitelist but that requires manual maintenance and sometimes can't
    be detected until *after* you've prevented delivery. In a large
    corporate environment, it's too late to add a server to a whitelist -
    you may have already lost an order, frustrated a customer, or at least
    added maintenance work for your e-mail admins.

    There is no single free one-step method for stopping all spam and
    nothing but the spam. 

    -- 
Ed Wilts, RHCE
Mounds View, MN, USA
mailto:ewilts@ewilts.org
Member #1, Red Hat Community Ambassador Program
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