Blocking 100% of SPAM

Question

Level 1

140 points

Blocking 100% of SPAM

I am currently using SpamAssasin, along with the great tool spamtrainer on our OS X servers.

However I am now looking into even more powerful SPAM blocking that will guarantee 100% blocking, such as services like SpamArrest:

http://www.spamarrest.com/tryit/index.jsp?1153522346495

Does anyone know of anything similar or close to being able to block 100% of SPAM? I was hoping that something like this could be installed on OS X server, instead of having to pay for a service.

Any suggestions are very much welcomed. Thanks.

Power Mac G5, Dual 2.0, Mac OS X (10.4.2)

Posted on Jul 21, 2006 3:55 PM

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Answer 1

UptimeJeff

Level 4

3,479 points

Jul 21, 2006 6:28 PM in response to Paul Wharff

You will never block 100% of all spam without blocking 100% of all mail, set realistic goals.

I would put effort into the art of SpamAssassin tuning, the effort may pay off with increased levels of accuracy.

Jeff

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Answer 2

Jul 21, 2006 9:03 PM in response to Paul Wharff

I beleieve you will just end up SpamArrest tuning instead of spam asssassin tuning.
it's all in how much time and effort you want to put into it.

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Answer 3

pterobyte

Level 6

11,104 points

Jul 22, 2006 12:10 AM in response to Paul Wharff

There is no such thing as 100% blocking. Anybody promising this is ridiculous (among other things).

There have been many discussions about how to better train spamassassin on this forum. Things like custom rules, allowing network tests and even greylisting (which is most likely what spamarrest does). It's all here.

Alex

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Answer 4

Paul Wharff Author

Level 1

140 points

Jul 24, 2006 4:34 PM in response to pterobyte

Maybe you didn't look at the link I posted above, but my friend sent me the link because he joined SpamArrest some time ago and since has not received a single piece of SPAM, whereas before he was getting on average about 100-200 a day. According to my math, that is 100% SPAM free.

So the short answer is NO, nothing similar to SpamArrest exists to install onto any UNIX/Linux or OS X server?

About SpamAssassin, I and the employee's I work with, have been redirecting all our spam to our OS X server for months and according to "spamtrainer", our database has grown to:

Displaying SpamAssassin Database Stats
0.000 0 10 0 non-token data: ham
0.000 0 13502 0 non-token data: spam

That's alot of SPAM in the database, but somehow I feel it's not working very well, because we're on the increase of SPAM and not a decrease.

I'm sorry for my whining, for I know that is what it is, but I feel a little helpless for a great solution. Also, I am using realtime blacklists inputted into SA:

relays.ordb.org
sbl-xbl.spamhaus.org

Can anyone point me in the right direction?

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Answer 5

UptimeJeff

Level 4

3,479 points

Jul 24, 2006 7:18 PM in response to Paul Wharff

You may see an improvement if you feed the system some more HAM.
You have over 13,000 SPAM messages and only 10 HAM.

This means you probably very few false positives (10 false positives vs 13,000 spam passed untagged.
Knowing this, you should be able to lower your tag threshold to around 3 to reduce the quantity of delivered spam.

Jeff

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Answer 6

Jul 24, 2006 8:18 PM in response to Paul Wharff

Spamarrest is annoying. You have to go to their website and fill out info and then it whitelists your address. Instead of you being inconvenienced by spam you inconvenience everyone who emails you.

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Answer 7

pterobyte

Level 6

11,104 points

Jul 24, 2006 11:46 PM in response to Paul Wharff

Maybe you didn't look at the link I posted above, but
my friend sent me the link because he joined
SpamArrest some time ago and since has not received a
single piece of SPAM, whereas before he was getting
on average about 100-200 a day. According to my
math, that is 100% SPAM free.

If it's really 100% then it can only be a challenge/response system. In other words I send you mail and spamarrest sends me a mail back asking me to go to a website for manual confirmation that I am a human being and that I did send this message.
As a sender, whenever I get such a request, I delete it. I can't be bothered to waste my time on this. So you not only reduce spam, but you also reduce the amount of people who want to talk to you via mail.

Try and add rules and network tests. Lots of information already in this forum.

Alex

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Answer 8

Paul Wharff Author

Level 1

140 points

Jul 31, 2006 2:00 PM in response to UptimeJeff

Hmmm, I never thought that providing it more HAM would actually help on the SPAM. Why is this?

Thank you, I'll give this a try.

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Answer 9

Paul Wharff Author

Level 1

140 points

Jul 31, 2006 2:02 PM in response to Timothy Gurske

Yes it may be annoying, however you only do it once and never have to again. I predict these kind of challenge and response systems will become more and more popular in the future.

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Answer 10

Paul Wharff Author

Level 1

140 points

Jul 31, 2006 2:03 PM in response to pterobyte

Thank you Alex.

Yes it is a Challenge and Response system. I will try to filter through these forums for more info on how to help our system in regards to SPAM.

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Answer 11

Jul 31, 2006 3:37 PM in response to Paul Wharff

What happens when a legitimate automated system sends you email, like your bank or a mailing list or a subscription service and others etc. You will never get those emails since there is no human being to answer the challenge/response system.

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Answer 12

Paul Wharff Author

Level 1

140 points

Jul 31, 2006 4:39 PM in response to Gino Cerullo

Excellent point! However I do know that some of these systems allow you edit your "white-list" so that you could take care of these special circumstances.

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Answer 13

Jul 31, 2006 5:29 PM in response to Paul Wharff

I figured that but you may not always know in advance what systems are trying to send you email and you may never know.

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Answer 14

davidh

Level 4

1,896 points

Aug 1, 2006 4:51 AM in response to Paul Wharff

Fix your spam setup by feeding it more HAM, adding rules and adjusting your spamfilter setting(s).

The bare minimum of spam and ham messages you need to feed to SpamAssassin are 200 each. That's a minimum starting point.

Any system that you take and fail to implement correctly, is going to disappoint you. Sorry but that's how it is.

Further reading here:
http://discussions.apple.com/thread.jspa?messageID=2224582&#2224582

http://discussions.apple.com/message.jspa?messageID=2634327

But if you must pursue a challenge-response system, yes one exists and is used by some.

I too would advise strongly against this, be prepared to lose (never receive) important legitimate email. This may work for your environment, for many it's not a viable risk.

http://www.afp548.com/article.php?story=20051127235810230

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Answer 15

Paul Wharff Author

Level 1

140 points

Aug 1, 2006 3:29 PM in response to davidh

David,

Thank you very much for the links to the very detailed discussions and AFP548 article! These should help me with my setup and I consider this solved!

Any other useful links is much appreciate, from anyone here.

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