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CNS - Spam Filter

KBCC Barracuda Email Security Gateway User 's Guide

This guide describes how you can use the Barracuda Email Security Gateway web interface to:

  • Check your quarantined messages
  • Classify messages as Spam and Not Spam
  • Manage whitelisting and blocklisting email addresses
  • Modify your User Preferences

Managing Your Quarantine Inbox

Receiving Messages from the Barracuda Email Security Gateway

The Barracuda Email Security Gateway sends you the following two types of messages:

  • Greeting Message
  • Spam Quarantine Summary Report

Quarantine Summary Report

The Barracuda Email Security Gateway sends you a daily quarantine summary report so you can view the quarantined messages you did not receive. From the quarantine summary report you can also add messages to your whitelist, delete messages, and have messages delivered to your inbox.

Note that the quarantine summary report only goes out if new quarantined mail is saved in your account since the last notification cycle. Each day the quarantine notification service runs for all users. If there is no new quarantined mail for your account since the last notification cycle, or if you have logged into your account since then, no quarantine summary report will be generated and sent to you for that same 24 hour period. Note also that links in the quarantine digest for viewing, delivering, whitelisting or deleting a message from the quarantine inbox expire in 5 days from the date the digest is sent out.

The following shows an example of a quarantine summary report:

Figure 1: Example quarantine summary report ('digest').


Using the Quarantine Interface

At the end of every quarantine summary report is a link to the quarantine interface where you can set additional preferences and classify messages as spam and not spam.

Logging into the Quarantine Interface

To log into your quarantine interface:

  • Click the link provided at the bottom of the Quarantine Summary Report (displayed above). The login page appears. 
  • Navigate to (use your KB credentials to sign in )

Using your Quarantine Inbox

After logging into the quarantine interface, select the QUARANTINE INBOX tab to view a list of your quarantined messages. When you first start using the quarantine interface, you should view this list on a daily basis and classify as many messages as you can. Clicking on an email displays the message.

The Barracuda Email Security Gateway has a Bayesian learning engine which, if enabled by your administrator, learns how to deal with future messages based on the ones you classify as spam and not spam. The learning engine becomes more effective over time as you teach the system how to classify messages and as you set up rules based on your whitelist and blocklist.

To effectively "train" your Bayesian database, you must classify at least 200 spam messages and 200 not spam messages from your Quarantine Inbox, which will train the Bayesian database as to what word or phrase patterns that appear, perhaps multiple times, throughout a message you consider to be valid content or characteristic of spam. Continue to classify an equal number of each type of message as needed.

The following table describes the actions you can perform from this page.




Delivers the selected message to your standard inbox.

Note: If you want to classify a message or add it to your whitelist, make sure to do so before delivering the message to your inbox. Once the Barracuda Email Security Gateway delivers a message, it is removed from your quarantine list.


Whitelist Adds the selected message to your whitelist so all future emails from this sender are not quarantined unless the message contains a virus or banned attachment type.

The Barracuda Email Security Gateway adds the sending email address exactly as it appears in the message to your personal whitelist.

Note that some commercial mailings may come from one of several servers such as, and a subsequent message may come from See the section on managing your whitelists and blocklists for tips on specifying whitelists with greater effectiveness.


Deletes the selected message from your quarantine list. The main reason to delete messages is to help you keep track of which quarantine messages you have reviewed. You cannot recover messages you have deleted.

Classify as Not Spam

Classifies the selected message as not spam. Note: Some bulk commercial email may be considered useful by some users and spam by others. For this reason, classifying such messages may not be very effective because users may counteract each others’ classification. Instead of classifying bulk commercial email, it may be more effective to add it to your whitelist (if you wish to receive such messages) or blocklist (if you prefer not to receive them).

Classify as Spam

Classifies the selected message as spam.

Changing Your User Preferences

After logging into your quarantine interface, depending on your account permissions, you can use the PREFERENCES tab to modify your quarantine and spam settings, and manage your whitelist and blocklist.

Changing Your Quarantine Settings

The following table describes the quarantine settings you can change from the PREFERENCES > Quarantine Settings page, depending on how the administrator has configured your account:

Quarantine Setting


Enable Quarantine

Whether the Barracuda Email Security Gateway quarantines your messages.

If you select Yes, the Barracuda Email Security Gateway does not deliver quarantined messages to your general email inbox, but you can view these messages from the quarantine interface and quarantine summary reports.

If you select No, all messages that would have been quarantined for you are delivered to your general email inbox with the subject line prefixed with [QUAR]:. The Barracuda Email Security Gateway administrator can modify this prefix.

Notification Interval

The frequency the Barracuda Email Security Gateway sends you quarantine summary reports. The default is daily. The Barracuda Email Security Gateway only sends quarantine summary reports when one or more of your emails have been quarantined.

If you select Never, you can still view your quarantined messages from the quarantine interface, but you will not receive quarantine summary reports.

Notification Address

The email address the Barracuda Email Security Gateway should use to

deliver your quarantine summary report. Leave this field blank to use the email address associated with your user account.

Default Language

The language in which you want to receive your quarantine notifications.

This setting also sets the default encoding for handling unknown character sets during filtering. All email notifications from the Barracuda Email Security Gateway are in UTF8 encoding.



Enabling and Disabling Spam Scanning of your Email

If you do not want the Barracuda Email Security Gateway scanning your emails for spam content, you can disable spam filtering from the PREFERENCES > Spam Settings page. From this page you can also change the default spam scoring levels that determine when your emails are tagged, quarantined or blocked.

When the Barracuda Email Security Gateway receives an email for you, it scores the message for its spam probability. This score ranges from 0 (definitely not spam) to 10 or higher (definitely spam). Based on this score, the Barracuda Email Security Gateway either allows, quarantines, or blocks the message.

A setting of 10 for any setting disables that option. The following table describes the fields on the PREFERENCES > Spam Settings page.

Adding Email Addresses and Domains to Your Whitelist and Blocklist

The PREFERENCES > Whitelist/Blocklist page lets you specify email addresses and domains from which you do or do not want to receive emails.

List Type



The list of email addresses or domains from which you always wish to receive

messages. The only time the Barracuda Email Security Gateway blocks a message from someone on your whitelist is when the message contains a virus or a disallowed attachment file extension.


The list of senders from whom you never want to receive messages. The Barracuda Email Security Gateway immediately discards messages from senders on your blocklist. These messages are not tagged or quarantined are not tagged or quarantined and cannot be recovered.

The sender does not receive a notice that the message was deleted, and neither do you. The only time a blocklisted email address is delivered is if the same email address also appears in your whitelist.


To whitelist senders or to add senders to your blocklist, follow these steps:

  1.  Go to the PREFERENCES > Whitelist/Blocklist page.
  2.  A list of your existing whitelisted and blocklisted addresses appears on this page.
  3.  To delete a whitelist or a blocklist entry, click the trash can icon next to the address.
  4.  To add an entry, type an email address into the appropriate field and click the Add button.

Tips on specifying addresses

When adding addresses to your whitelist and blocklist, note the following tips:

  • If you enter a full email address, such as[1], just that user is specified. If you enter just a domain, such as, all users in that domain are specified. 
  • If you enter a domain such as, all subdomains are also included, such as and
  • Mass mailings often come from domains that do not resemble the company’s website name. For example, you may want to receive mailings from, but you will find that this site sends out its mailing from the domain Examine the From: address of an actual mailing that you are trying to whitelist or blocklist to determine what to enter.

Changing the Language of the Quarantine Interface

You can change the language of your quarantine interface by selecting a language from the dropdown menu in the upper right corner of the QUARANTINE INBOX and PREFERENCES tabs. Supported languages include Chinese, Japanese, Spanish, French, and others. The language you select is only applied to your individual quarantine interface. No other user’s interface is affected.