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What is MailScanner?

Every LinkSky hosting account comes with a very powerful anti-spam utility called MailScanner, located within the Mail section of your cPanel. The MailScanner utility is the front end for a series of anti-spam preventions which are constantly at work to analyze and score incoming messages. This dynamic scoring system helps our members determine the difference between spam and legitimate email.

THE ELEMENTS OF SPAM SCORING

Applied Bayesian intelligence: One of the most remarkable features of your LinkSky-hosted MailScanner is the Bayesian system that is employed behind the scenes to examine the overall pattern of email coming to your account (and others within our system), and thereby achieving a higher degree of accuracy over time.

Bayesian spam filtering (BAY-zee-ən; after Rev. Thomas Bayes) is a statistical technique of e-mail filtering. It makes use of a naive Bayes classifier to identify spam e-mail. Bayesian classifiers work by correlating the use of tokens (typically words, or sometimes other things), with spam and non-spam e-mails and then using Bayesian inference to calculate the probability that an email is or is not spam. Source: Wikipedia.

Bayesian spam filtering is a very powerful technique that can tailor itself to the email needs of individual users, and gives low false-positive spam detection rates that are generally acceptable to users. In other words, the LinkSky hosted Bayesian system will "look at" incoming email patterns server-wide (not just for your own email account), then collect and analyze system-wide trends, adjusting the probability scoring as the trends develop. The few spam-emails that may initially slip by with a lower overall score, will score higher as the Bayesian system "learns" more about the particular email broadcast arriving at the server. In this way, it is a very powerful fail-safe so that even the most covert, well engineered spam will, in time, be red-lined as spam by this system.

Other facets of the MailScanner system working together to defend your LinkSky hosted account from spam are: Barracuda Networks, spamhaus-ZEN, spamcop.net, SpamAssassin, ClamAV, Vipuls Razor, DCC and an array of real-time, anti-spam black listing services.

Also of note: By default your LinkSky hosted MailScanner system will automatically remove/quarantine the majority of viruses attached to email messages. This does not eliminate the need to maintain solid security on your desktop or mobile device, and to keep your email programs up-to-date.

HOW WILL I KNOW ITS WORKING?

MailScanner assigns a numeric score to each email. MailScanner then assigns each message into one of three categories: 1) Legitimate mail, 2) Low-scoring spam, or 3) High-scoring spam.

The high-scoring spam is deleted at the server level and you never see it. Legitimate mail goes through as expected. The messages that MailScanner determines to be low-scoring spam are tagged with "-s- LIKELY SPAM" in the subject line of the message.

KEEPING INBOUND SPAM OUT OF YOUR IN BOX

One very useful way to take advantage of MailScanner's scoring is to use the "filters" or "rules" that come with most email programs.

a - Open your email program and establish a new email directory (folder). Name it something like "spam-suspects."

b - Next, set up an email filter to divert all incoming email to your new "spam-suspects" email directory WHEN the subject contains: -s- LIKELY SPAM.

c - You'll need to periodically glance through your spam-suspects directory to look for the possibility that any legitimate message has been inadvertently spam tagged. This is unlikely, but no anti-spam system is 100% perfect, 100% of the time. If you find a message you want to keep, move it to your IN box. Then simply "select all" and delete all of the messages in your "spam-suspects" folder with just a few keystrokes.

Setting up a filter like this makes your email program do the work of sorting your mail, so that you don't have to!

MAKING ADJUSTMENTS TO MAILSCANNER SETTINGS

We find that the scoring threshold defaults are quite accurate as a general rule. However, if you find that too much spam is getting through untagged, then you can adjust the scoring threshold for your account. Log into your cPanel. In the Mail section, click the Mailscanner link/icon. MailScanner-1.jpg

On the next page, click the Other Settings link. Here you will see two scoring levels. One for the high scoring, the other for low scoring.

MailScanner-2.jpg

Usually the high scoring should be left at the default of 20, but you can lower it if you wish. Just be aware that any message that scores over this threshold will be deleted and is not recoverable. The low scoring default setting of 5 is more commonly adjusted. Lowering this to 4 will tag more of your incoming email as potential spam (with the -s- LIKELY SPAM in subject line), while raising the threshold setting to 6 will allow more marginally suspicious email to come though to your IN box untagged. If you decide to make changes, try it for a few days and come back for more adjustments if needed.

The other configuration in your MailScanner is the Whitelist/Blacklist area.

MailScanner-3.jpgMailScanner-3.jpg

Before blacklisting an email address, you should first consider that spammers will never use their own email address to send from. They are more likely to "volunteer" an address from a random list. To blacklist against these addresses would be an endless task without much result, because the addresses constantly change. A better use of the blacklist feature might be if there is an individual that is sending harassing emails to you or to your company. Inserting their email address in the blacklist field is an effective method to prevent their messages from getting to your IN box.

The Whitelist field is a list of email addresses which you do not want virus filtered, or analyzed for spam scoring on any level. In our opinion, this should be rarely, if ever, used. If someone is sending you email which is legitimate but is being spam tagged (which would be rare), we recommend investigating with the individual why this happens rather than just whitelisting their email address. Perhaps they are using a questionable, if not outright blacklisted server for their email services. If you reveal the full header of the email, you will be able to see the actual Mailscanner score with a detailed breakdown. For information on revealing the full header of an email message, click here. LinkSky staff would be happy to help you with this task.

NOTE: Wildcards can also be used by mail scanner in both the whitelist and the blacklist, like this -- *@aol.com -- which would whitelist or blacklist everyone sending you email from aol.com. We don't recommend using this except in the most extreme circumstances. AND, we definitely do not recommend whitelisting your own email addresses (*@YourDomain.com). Such a whitelisting may result in all of your LinkSky mailboxes being flooded with unfiltered spam and viruses. Spammers often use programs that will insert the same address in both the FROM and the TO fields of the spam messages they send. They do this in hopes that the target email account has whitelisted their own email address. When you whitelist your own address you become vulnerable to this method of attack.

Spam is considered the number one problem on the internet and it managing it consumes an enormous amount of resources. Taking advantage of the tools outlined above can help reduce this problem. If you have questions about any of the features in the article, please contact us. We'll be happy to assist.

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