Barracuda Reputation is a database maintained by Barracuda Central and includes a list of IP addresses of known good senders as well as known spammers, or IP addresses with a "poor" reputation. This data is collected from spam traps and other systems throughout the Internet. The sending history associated with the IP addresses of all sending mail servers is analyzed to determine the likelihood of legitimate messages arriving from those addresses. Updates to Barracuda Reputation are made continuously by Barracuda Central engineering.
On the Inbound Settings > Anti-Spam/Antivirus page, it is strongly recommended that you select Use Barracuda Reputation Block List (BRBL).
Subscribe to External Block List Services
Use the Inbound Settings > Custom RBLs page to use various block list services. External block lists, sometimes called DNSBLs or RBLs, are lists of IP addresses from which potential spam originates. In conjunction with Barracuda Reputation, the Barracuda Email Security Service uses these lists to verify the authenticity of the messages you receive.
Several organizations maintain external block lists; if you are using a paid or free external block list you can leverage the block list if you are within the terms of service. Adding a free RBL service will often not work when added to the Barracuda Email Security Service. A paid subscription to a RBL service is required. This subscription will provide you with your own custom RBL hostname that you can add to the Barracuda Email Security Service.
Be aware that block lists can generate false-positives (legitimate messages that are blocked). Messages blocked due to external block lists or the BRBL are the only blocked messages that are not sent to the user's Message Log.
Email Categorization
Email Categorization gives administrators more control over what they believe to be spam, even if those messages do not meet the technical definition of spam. Most users do not realize that newsletters and other subscription-based emails, while they are considered to be bulk email, are not technically unsolicited - which means that they cannot be blocked by default as spam. The senders of these emails may have a good reputation, but the user may no longer want to receive, for example, a mass mailing from a club or vendor membership. The Email Categorization feature assigns this type of email to categories that display on the Inbound Settings > Anti-Spam/Antivirus page, and the administrator can then create block, quarantine, or allow policies by category. When set to Off, no categorization scanning is performed.
Supported categories:
- Corporate Emails – Emails sent from Microsoft Exchange Server that involve general corporate communications. This does not include marketing newsletters. The default action is Allow.
Transactional Emails – Emails related to order confirmation, bills, bank statements, invoices, monthly bills, UPS shipping notices, surveys relating to services rendered, and/or where transactions took place. The default action is Allow.
- Marketing Materials – Promotional emails and newsletters from companies such as Constant Contact. The default action is Allow.
- Mailing Lists – Emails from mailing lists, newsgroups, and other subscription-based services such as Google and Yahoo! Groups. The default action is Allow.
- Social Media – Social media notifications from sites such as Facebook, LinkedIn, and Twitter. The default action is Allow.
Email Categorization supports the following actions, in the following order of precedence:
- Allow – Deliver the message.
- Block – Do not deliver the message.
- Quarantine – Put the message in quarantine if there are no other checks for other categories that can result in actions of higher precedence (Allow, Block).
- Off – No action is taken. All other spam scanning and policy processing is performed on the message.
Messages that have been categorized appear in the Message Log with Email Categorization (category) as the Reason. The administrator can then select one or more categorized emails and click Recategorize to change the category, as shown in Figure 1. This information is submitted with the sender IP for Email Categorization. Optionally, you can assign a 'custom' category by selecting Other in the drop-down for a particular email. See the Message Log help page for details.
Figure 1. Recategorize the Message from Corporate to Marketing Materials