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Proving Which Spam Filters work Best
pirateninja writes "Dr. Gord Cormack decided to find and prove what the best spam filter is. In his study he looked at the major spam filters (DSPAM, SpamAssassin, etc.) along with those submitted by various academics. The results are quite surprising, with a previously unheard-of spam filter, which uses ideas from various compression algorithms, performing the best overall. He recently presented the results and methodology used in a presentation titled 'Spam Filters, Do they Work? and Can you prove it?'" Note that this is a video of his presentation.
400 Megs that is.......
... the ones which have worked best (for me) are Bayesian Spam Filters (A Plan for Spam, SpamBayes - a free filter) and CRM114 The Controllable Regex Mutilator (Paul Graham mentions it here). I've always had a very high success rate with these.
Vivin Suresh Paliath
http://vivin.net
I like
Its round robin mirrored accross a whole bunch of different servers so if youre only getting 8kb/s you could try cancelling and downloading again and seeing if it goes faster.
And turn off SMTP VRFY. Either that, or having windows systems @ my ISP managed to get the address associated with my account on spam lists. This is an address that's *only* used internally by my ISP (I use pobox or my own domain whenever someone asks for an address). Even that wasn't enough to provent it from getting harvested. :-(
"The urge to save humanity is almost always a false front for the urge to rule." --H.L. Mencken
We use Brightmail on our campus and our users love it with its very low false positive and pretty accurate flagging of SPAM. Another campus uses DSPAM and some people are up in arms at the prospect of losing their Brightmail to switch to DSPAM. Personally, DSPAM isn't nearly as good and has flagged many legitamate messages and sent them to the Junk folder.
I also echo a gripe of other posters. Its nice to have a video but 500MB video file it a bit much. A 50KB pie chart or bar graph would have been nice.
The spammers actively try to subvert the more popular filters. That gives a lesser-known one a decided advantage, one which will go away as it becomes more popular.
As with most choices like this, factors such as ease of use, speed, and resource efficiency can overshadow selectivity. No system is perfect, so it's perfectly reasonable to go with a system that's pretty good if you already are using it, rather than switching to the latest cool thing.
I have found that using two dissimilar systems in a chain is quite effective.
Raise your children as if you were teaching them to raise your grandchildren, because you are.
The official tests of spamfilters were done in last year's TREC conference, you can read the writeup here (or pdf overview).
You can duplicate those tests yourself if you download the evaluation toolkit (GPL). It's a modular system where you can add a mail corpus (either one of the public TREC ones, or you can make your own trivially), and add a spamfilter package (there are 10 or so to download from the web, or create your own as per documentation).
There's also a video talk given at Microsoft research which should cover pretty much the same ground, if text mode is slashdotted :).
There's a new scheduled test towards the end of the year at TREC 2006.
I hope you also have another word, because the Postini service is incredibly bad. I had it enabled on my account at acm.org, and the Postini system was generating roughly one false positive for every 10 true positives. I disabled the Postini filtering and started using Spamassassin. Both the false positive and false negative rates are much improved. Among the traffic that Postini was flagging as spam were the Wikipedia article of the day, my daily email from musicbrainz.org, all messages to the BATN mailing list, many replies to my items for sale on craigslist, and other kinds of completely legitimate traffic. Among the mail they chose to deliver were messages in Korean, Cyrillic, other scripts I can't read, and known viruses.
Their main problem is the system doesn't learn. Using their web interface, I look through the spam folder and request delivery of all the false positives. The next day, nearly-identical mails are still generating false positives. You'd think it would be easy these days to design a filter that learns from negative reinforcement.
Gordon Cormack and Thomas Lynam
Full Text, May 29, 2006 - PDF Format
http://plg.uwaterloo.ca/~gvcormac/spamcormack.html /
The only thing new in this world is the history that you don't know.[Harry Truman]
This paper's a complete waste of time.
He tested spamassassin 2.3 - that's ancient! I'd imagine the other tools are similarly obsolete.
We currently use SA 3.1.4 with a well-trained Bayes database and Razor, Pyzor, and DCC.
Throw in a few custom rules and a selection of rules from http://www.rulesemporium.com/ and the results are outstanding.
With the new sa-update feature the core rules are updated between point releases, which came in useful this week dealing with the new image spams which seemed to be designed to avoid detection by spamassassin. Thanks Theo.
And the folk on the spamassassin-users mailing list really rock.
However, note that we are talking about two separate scenarios:
- a home server for an user with no responsibilities
- a project/ISP-wide mail server
In the former, delaying mail for weeks may be acceptable -- but even then, I wouldn't touch something with a 1:500 false positive ratio with a long stick.The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.
Because many clueless morons have email spam filters administered by the clued;
Not making any judgements but the "clued" category includes Gmail, Yahoo Mail,
AOL, corporate IT managers and university mail server admins.
Here is a torrent I made of the xvid file. It should work (I hope).
Vivin Suresh Paliath
http://vivin.net
I like
I receive (no kidding) around 600 spam mails per day, versus approximayely 30 real e-mails. I've been using dspam for over a year now (with very faithful training), and there is maybe 1 false positive every few weeks (less than 1 in 10.000) and every few days a few (usually "new") spam mails get through, which I ofcourse immediately train, to never see those kind again. So I am very very positive about dspam. What I do miss though is something like a good and reliable service (better than the RBL's I know) that can block SMTP clients on the fly (like DSL home users and such) to reduce the immense load on our mailservers (I work for an ISP) caused by all the spam (that also has to go through a virus scanner, clamav).
Here are the slides from the 400MB video presentation.
Hey, we can't help it if people decide to post our videos to ./ and Digg!
r text_gi2&cfg=cn-rtext.cfg
[/innocence]
Here are UW's traffic stats, in case anyone's interested:
http://noc.uwaterloo.ca/cgi-bin/14all.cgi?log=cn-
Also note the spikes on Monday and Tuesday from when we posted our last two talks.
True, but as I per below, there's literally mounds of baked clay tablets because they are so indestructable. Apparently they used to get shovelled into foundations and the like. The estimate I heard was that at current rates it will take scholars several hundred years to translate what we've found already. Compare that to parchment records where the discovery of even a few new scraps is a major event (http://news.bbc.co.uk/1/hi/sci/tech/5235894.stm and particularly http://news.bbc.co.uk/1/hi/world/europe/5216320.st m). Point is in the race for the most successful long term storage mechanism cuniform on baked clay is way ahead of the field, nothing else comes close.
u rtime_20040603.shtml
Excellent 'In Our Time' programme on Babylon and it's Literature here - http://www.bbc.co.uk/radio4/history/inourtime/ino