How to Block Spam and Viruses in Lion Server

By John Rizzo from Mac OS X Lion Server For Dummies

Lion Server is integrated with several types of filtering software to keep spam and viruses from reaching users. It uses the open source spam-blocking software called SpamAssassin, which does a statistical analysis of incoming e-mail to determine whether it’s probable spam.

It also supports the blacklisting of certain e-mail servers, rejecting e-mail from known spammers. For this, Lion Server communicates with servers of the Spamhaus Project, an international not-for-profit organization that collects spam blacklist data. Lion Server also includes software that scans incoming messages for viruses: the open source ClamAV.

Set spam and virus blocking with the Server app

To access the filtering settings from the Server app, click Mail in the sidebar and then click the Edit Filtering Settings button. There are three settings:

Enable Virus Filtering: This option is either on or off.
Enable Blacklist Server Filtering: This check box specifies a blacklist server to prevent spam from known spam servers from reaching you.

If you select this option, the default is zen.spamhaus.org. You can change this setting, if you like.
Enable Junk Mail Filtering: This check box activates the slider that you can use to set the severity of filtering.

The higher you set the slider, the higher the chance that junk e-mail will be detected. Any messages that are deemed to be spam are marked JUNK and forwarded to the user. This setting also tells the Mail server to remove all e-mail messages it suspects of containing viruses and to place them in this folder: /var/virusmails.

Set spam and virus blocking with Configuration Assistant

The Configuration Assistant is accessed from Server Admin: Select Mail in the sidebar, click the Overview tab, and click the Configure Mail Service button. The Filters screen is similar to that of the Server app, with some more detail but no access to the blacklist filtering:

Scan for Junk Mail presents the same slider as in the Server app.
Scan Email for Viruses includes a pop-up menu with a choice of deleting, redirecting, or bouncing infected messages.
Update the Virus Database lets you set the number of times per day for the server to check virus databases.

Set spam and virus blocking with Server Admin

Using Server Admin’s Mail Settings window to set spam and virus blocking gives you more choices than either the Configuration Assistant or the Server app.

Here’s how to bring up the Settings window for configuring filtering:

In Server Admin, click the triangle to the left of your server to expand the list of services.
Click Mail from the list; then click the Settings icon in the toolbar.
Click the Filters tab.

Server Admin’s spam and virus filter window appears.