Spam Weighting...

Forum for MailWasher Pro 7 and/or older 2011/2012 versions.
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Firetrust Monkey
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Joined: Mon Jun 13, 2005 6:27 pm

Spam Weighting...

Tue Aug 24, 2010 11:21 pm

Spam Weighting and all it's complicated glory.

Actually it's not complicated at all, just grab a coffee and chocolate biscuit and settle in for a bit of a read.

The old MailWasher used a set of rules to determine if a message was to be marked as spam or not. For example, if the sender was on your Friends List, the email would always be good no matter what any of the other Spam Tools said, except if the email was thought to a virus.
There were many various combinations of rules, and they could lead to any number of relatively complicated scenarios, the worst aspect of these Tools was that they always worked independent of each other.

Here's a flow chart to give you an idea....
flow_chart.png (32.46 KiB) Viewed 31919 times

MailWasher 2010 has a new system where the Spam Tools combine and outcome is determined on that total score. Now this can produce some unexpected results if you're used to the old rules based system, but once you spend a few minutes understand the new weighting system you could quite easily alter MailWasher to perform exactly as you want, or simply leave it and correct as necessary.
This makes it harder for spammers to come up with tricks that might bypass one Spam Tool over another.

When an email arrives into MailWasher it has a score, that score starts at 0. Positive aspects of the email such as being on your Friends List add positive scores, whilst negative aspects of the email like being on the Blacklist adds a negative score.

If the emails total score is at +50 or greater, then the email is considered good
If the emails total score is at -50 or greater, then the email is considered spam
If the emails total score is between the range of -50 through to +50 then the email is considered unknown

You can at any time view the full evaluation summary by right clicking the message and selecting Show Evaluation Details. Clicking directly on the Sidebar produce a smaller or larger representation of the same information depending on current view, and you can drag this Sidebar out or back in as needed.
side_bar_full.png (85.81 KiB) Viewed 31919 times

So put in practice:

An email arrives and its score starts at 0, then MailWasher sees it matches your Friends List which adds +80. The total score is therefore +80 and the email is considered good.

Pretty simple this now to the unexpected results that you might not be used to.

Now let's suppose the email is marked by your Friends List but the Bayesian/Learning thinks the email is quite spammy, and scores the email at -100. This gives the email a total score as -20, so MailWasher marks the email as unknown. This allows you to correct MailWasher and classify that email as good, then in turn after you Wash Mail and that email is trained as good future emails like it are more likely to be considered good and not spam.

But you might be thinking if it's on my Friends List it should always be good. Well, many spam emails forge the sending address, in fact the only spam I get comes from addresses of legitimate senders that I know.

Of course everyone is different, so under Settings >> Spam Tools >> Spam Ratings >> you can set here how much authority each Spam Tool has.

If you want your Friends List to always be treated with the highest authority then just set the slider all the way out to a +200

If you want Blacklisted addresses to always be treated as spam, then again give it the highest authority to -200

If however, like me you get a lot of spam and the senders address is known to you, you might want to leave the Friends List where it is and instead set the other Spam Tools like FirstAlert to a higher weight.

spam_ratings.png (27 KiB) Viewed 31919 times

Other things you can do to your advantage :

Auto-deleting :
You can set MailWasher to AutoDelete here, the AutoDelete in this screen works off the total. So if for example you set it Automatically delete anything higher than -250 the email would have to have been hit by multiple Spam Tools for it to be removed. A warning though, you should not AutoDelete early on, to make sure you won't be deleting any mail you really wanted to keep.

This can work to your advantage for better protection. Suppose you set your Blacklist to -200 and you also setup your AutoDelete to remove anything at -200. This means that if for some reason MailWasher thinks the email is good, but it's also on your Blacklist the email will remain in view which is useful if you accidentally blacklist a good sender.

There are many variations to consider, everyone has different needs though we think out of the box the settings are right in most cases, but you can always alter to your own preference too.

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