How Spam Filtering Works

If you have questions about why someone can't get emails to you or why they go to spam or get bounced, this article should answer most of those questions.

Level 1 - Misconfigured mail servers and black lists.

If the person that is attempting to send to you gets a bounced message, then they have been stopped by level 1.  The bounced message that the sender receives back has all the information that explains why their message bounced.   That message will not only contain a brief message as to why they were bounced but also a link to a page that explains it in detail.  Possible reasons are in two categories.

1. The sender is listed in an RBL (Realtime Black List).   We do not control realtime blacklists but we do use them to block domains that have gotten themselves listed.  Some black lists that we use are Spamcop, Barracuda and others.   If the bounced message indicates that the person is blacklisted,  they need to contact their email provider and have them correct the problem.   There is nothing we can do to get them unlisted, only their email provider can do this by contacting the black list and have their IP address delisted.

2. The sender's mail server is misconfigured.   This sometimes happens to small mail servers that companies host themselves and haven't taken all the proper steps to set up their mail servers correctly.  This is how we differentiate between real mail servers vs trogan infected home computers.

This level of spam filtering filters over 90% of all email coming to our servers.   The remaining 10% is then examined by level 2 of our spam filtering.

Level 2 - Close message examination

Once a message has passed thru level 1, we examine the message closely running over 50,000 tests on the message and giving it a spam score.   This is where your user controlled spam settings are used.   Messages that fail this test are quarantined in your spam folder.    If you are not receiving a message that you expected, check your spam folder to see if the message is there.

You can log into your control panel or contact us to have your personal spam filter settings adjusted and/or whitelist or blacklist specific email addresses or domains.

The way this level of spam filtering works is score based.   After we examine a message, we give it a spam score..  The more spammy it is, the higher the score.   You can set the spam score threshold in your control panel settings.   We recommend starting with a score of 5 which will cause messages with a score of 5 or higher to be quarantined in your spam folder.   Messages less than a 5 get delivered to your inbox.     

You can also whitelist specific senders and/or domains which will make messages from those people deliver to your inbox and not be quarantined as spam.

To adjust your spam filter settings, login to your control panel and click on the mail tab.  Then click your email address and then the spam tab.   Click on advanced settings and you will see your spam score setting there as well as a whitelist and blacklist.  Adjust as desired and click save.   The higher you make the spam score the more spam you will get and the fewer messages that will end up quarantined.   You may enter people into the blacklist or whitelist by either entering their email address or, their entire domain.   To enter an entire domain the entry should look like this..  *@domainname.com.

For more information as to how to get to your control panel and adjust your settings, see This article How Do I Adjust My Spam Filter Settings.




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