One of the most common questions I receive from Domino administrators is about e-mail filtering. Administrators want to block or limit unwanted inbound e-mail. The unwanted e-mail may be "spam" (unsolicited advertisements), e-mail from a normally trusted party with a virus attached, or may be e-mail that is solicited by a user but is not appropriate for the organization. An example of the latter might be any e-mail with a large attachment, say greater than 1MB. Because this question is so common, and because there are some new solutions to the problem, I decided to address the issue in this month's tip.
First, let me make a point about what administrators realistically can achieve. Preventing spam and viruses is not an option. The people who send spam and create viruses are too clever, and every time you close one door to them they find another way in. What you can hope to do, however, is reduce the amount of unwanted e-mail your organization receives. With this goal in mind, let's look at the methods at your disposal.
The first line of defense against unwanted e-mail, and the least expensive, is to use the e-mail filtering controls that are built into Domino. These are located in the Domino Public Directory (names.nsf). Go to the view Server / Configurations. Open the configuration document for the server you want to control. Open the tabs Router-SMTP / Restrictions & Controls / Restrictions. (And the nearby tab SMTP Inbound Controls.) You will see a number of options here that allow you to block known spam domains and limit message size. Most of the options are self-explanatory, but for full details see Domino Administration Help / Index / Spamming / Preventing.
For more robust e-mail filtering, you should consider the third-party products that are available. Some of these products provide far better spam control and size limits than Domino offers, and have additional features such as virus scanning, keyword filtering, e-mail archiving, and customizable filter rules. Among the most popular products are:
- Mail Attender from Sherpa Software
- Mail Warden from BVRP
- Iron Mail from CipherTrust
- SuperScout E-mail Filter from SurfControl
- ScanMail from TrendMicro
- Group Shield Domino from McAfee
Two important caveats to keep in mind as you evaluate these products:
- Some of the products work with SMTP e-mail format. They operate on messages that are coming into (or out of) your organization, but not on 'pure Notes mail' that is delivered between Notes clients. In other words, they allow you to block an offensive e-mail from the outside world but not from one of your own users.
- Each product has strengths and weaknesses. Be sure to have a clear idea of what you want to accomplish (virus control versus anti-spam, for instance) and evaluate the products with your goals in mind.
You can find more information about these, and other, third-party security products on my web site DominoSecurity.org. Go to the home page, scroll down a bit, then click on Products. Do you have comments or questions on this tip? Visit our security forum and post a question or comment.
Chuck Connell is president of CHC-3 Consulting, which helps organizations with all aspects of Domino and Notes, especially administration and security. CHC-3 helps companies to outsource their Domino administration needs via the web site DominoAdministration.comand runs the popular security site DominoSecurity.org.