[Air-l] screening out spam

James Howison jhowison at syr.edu
Tue Aug 17 09:24:45 PDT 2004


I use spamassassin and really am pleased with the result.  I reckon I 
get about 10 spam in my inbox a week (and maybe 1 false positive a 
month).

I have a unix account and use fetchmail to drag all my email to the one 
account on the unix box.  As it comes in it is filtered by spamassassin 
and, using procmail, put into a Spam IMAP folder.  I then access the 
email by IMAP client and webmail and it is all in the same folders.

Talk to whomever does your mailserver and urge them to use at least 
some spam-filtering software.  The free stuff works just as well as the 
expensive stuff.

OUr mailserver also uses the http://www.spamhaus.org/ blacklist which 
is intended to identify IP addresses of know spammers but also home 
machines that are acting like they have mailing-viruses installed.  
That bounces a lot of mail but I have never had a false positive with 
it (and I was very careful at first to check all the bounces).

The bottom line is that you have to go collaborative with this stuff 
can't fight them alone.

--J

On Aug 17, 2004, at 8:24 AM, Tom Diffenbach wrote:

> There's another side effect to a strict set of filtering rules: you 
> might
> make it too hard for email that you'd like to get thru.   From the 
> outside
> world, I deal with academic email addresses where incoming email is
> "scored".  If I want to be sure an email gets thru, I have to 
> repeatedly use
> words like "Professor" or the name of the school to raise my mail's 
> score in
> case a pic or some content might have somehow lowered its score.  I 
> make the
> effort; I wonder how many others quit trying to communicate with
> academicians inside these walls.  I have found in non-email contacts 
> that
> some professors are not aware of the details of their school filters.
>
> ----- Original Message -----
> From: "Frank Schaap" <architext at fragment.nl>
> To: <air-l at listserv.aoir.org>
> Sent: Tuesday, August 17, 2004 8:03 AM
> Subject: Re: [Air-l] screening out spam
>
>
> Gary Thompson wrote:
>> The recent spate of messages from those trying to unsubscribe reminds 
>> me
>> that about 2/3 of everything I get via e-mail—even with an academic
>> address—is spam. I’ve got my “rules” set up so as to try to catch some
>> of this:
>
> Since you talk about "rules" I suppose you're using Microsoft Outlook
> (Express).
>
>> --if the subject line contains certain keywords, e.g., “market,”
>> “drugs,” “investment,” “penis,” “casino,” then it goes into my trash 
>> box.
>> --if the from line contains “admin,” then it goes in the trash box
>> --if the “to” says “undisclosed recipients,” etc.
>>
>> I’m wondering whether others have had success with similar rules, as
>> opposed to installing spam-killing software (and as for that, how well
>> does it work, when spammers garble key words so as to avoid screening,
>> e.g., Vi*ag*kra or other combinations).
>
> It helps a little... but unless your e-mail client lets you write
> sophisticated regular expressions into the rules (which Outlook doesn't
> afaik), you quickly end up with countless not terribly effective 
> rules. I
> tried this too before our department admins installed server side spam
> filtering on the Exchange server.
>
> One of the reasons that 'professional' spam fighters have moved beyond
> 'mere' rule based filtering is that because spamfilters have to be made
> available to the public, dedicated spammers will quickly find ways 
> around
> static rules for filtering spam.
>
> A Bayesian spamfilter is a more dynamic type of filter that goes 
> through a
> learning period in which you tell it which messages are spam and which
> messages are ham. It classifies a number of characteristics of these
> messages and depending on their statistical occurrence in either 
> category
> incoming messages are sorted into either the spam or the ham category.
>
> Mozilla based e-mail clients such as the Mozilla Suite and Thunderbird
> <http://mozilla.org> contain bayesian filters. Personally I'm very 
> pleased
> with the end result. I haven't seen a spam message up close for a long 
> while
> and I haven't had any false positives after a rather short training 
> period.
> The Mozilla based clients support both POP and IMAP.
>
> But, if you just have to use Outlook to access your department's 
> Exchange
> server and your department admins refuse to install spamfiltering on 
> the
> server, you can run a bayesian filter in your own Outlook install (if
> they've given you enough permissions to install it). Have a look at
> Spambayes <http://spambayes.sourceforge.net/>
>
> Eventually I guess we'll see some sort of authentication system that 
> makes
> e-mail traceable. For the moment I just try to keep my personal, 
> non-list
> related e-mail addresses off the web and out of newsgroups. For that 
> kind of
> use I set up free throw-away accounts that I use for a couple of months
> untill they become useless.
>
> HTH
>
> Frank.
>
> -- 
> My Personal Portal (TM)
> http://fragment.nl/
>
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