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I'm receiving SPAM email in my Outlook inbox. How are these messages getting through?
Q7: I'm receiving SPAM email in my Outlook inbox. How are these messages getting through? Why doesn't our anti-spam system stop these messages? Why are legitimate messages sometimes quarantined as SPAM?

A: Spam email is a problem facing all organizations (schools, businesses, government) that use Internet email. CWSL is not being singled out, nor are we sitting idly by allowing massive amounts of spam email to clog our email system. The CWSL email system agressively filters unwanted email by employing multiple levels of anti-spam filtering to the incoming email stream.

First, our incoming email is filtered by a Barracuda Networks Cloud service. This blocks a percentage of spam and email viruses before it even reaches our network.  Next, as email enters our network, it is analyzed by an on-site email security appliance, also by Barracuda Networks. It also blocks email that has an extremely high spam index. If it identifies an email as being "possibly" spam, it allows the message to come through, but tags the subject with [possible spam].  The final level of anti-spam filtering occurs when your Outlook email software reads your inbox on our Exchange server. Any messages that are deemed spam by Outlook's Junk E-mail filter are immediately moved into your Junk E-mail folder.

Important Note: the end user (you!) does not have the ability to whitelist email messages that are blocked by either of the Barracuda filtering layers. It's very rare that this occurs. If it does, please contact HelpDesk and we'll address this for you.  However, if messages are ending up in your Outlook Junk E-mail folder, you can "whitelist" these messages yourself. Just right-click on the message, select Junk, then select one of the "add to Safe Senders" options.

These various filtering layers work to eliminate the vast majority of spam entering our network. For example, the Barracuda services filters over 80% of the incoming email stream as spam! Let me repeat that, because it's worth repeating. Around 80% of the email sent to addresses from the Internet is spam, and is blocked before it ever reaches our email server or your inbox!

So why isn't it able to stop all spam messages, you may ask. Why is a message that is so obviously spam (to the human eye) allowed to get through a spam filter? There are several reasons for this (and to answer this we have to put our geek hats on for a bit). First, keep in mind that it is relatively easy for the cognitive abilities of (most) humans to quickly identify a message as spam. It is simply not feasible, though, to have a human scan every message coming into a network (our network, for example, receives over ten thousand messages daily). But for a computer algorithm, it's not so simple to positively identify spam. Computer algorithms can't look at a message the way a human does and simply "know" that a message is spam. It has to perform various tests to determine the nature of the message...and it's doing this on perhaps hundreds, if not thousands, of messages per minute. Therefore, even the most effective anti-spam systems on the market are able to correctly identify about 95% of the incoming spam. Some spam inevitably gets through. For this very same reason, the algorithm sometimes will mistakenly identify a legitimate message as spam. This doesn't happen often, but it does occur.

Another reason that spam is sometimes able to get through is that the creators of spam are always working to find new ways to circumvent anti-spam systems. It is a never-ending cat-and-mouse game. There simply is no 100% effective means of stopping spam. There is no "silver bullet" device that is capable of stopping all spam email. Spam is a global problem plaguing every organization that uses email. Fancy spam filtering appliances and email client software, working together, can put a sizeable dent in the problem, but some spam email will inevitably get through. At that point, the last line of defense is the "Delete" key.

Some key points of spam filtering to remember:

  • Spam is a global problem facing all organizations using Internet email.
  • Spam detection devices can stop the majority of spam, but not all of it.
  • Occasionally, legitimate messages will be incorrectly identified as spam.
  • The vast majority of spam entering the CWSL network is either blocked completely or quarantined before you ever see it. The little bit of spam that does come through is a trickle compared to that which was sent to you and stopped by the spam filters.
  • If you receive spam messages in your inbox, please do not feel it is necessary to report this to us. Simply delete the message.

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