How to Set Spam and Virus Blocking in Lion’s Server Admin
Using Server Admin’s Mail Settings window in Lion Server 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.
Click Mail from the list; then click the Settings icon in the toolbar.
Click the Filters tab.
Statistical spam filtering
At the top of the Server Admin Filters window is the Minimum Junk Mail Score slider bar. Setting the slider toward the left (Cautious) lets more spam get through to users, where their own spam filters deal with it. Setting it toward the right (Aggressive) sends fewer junk mail messages to users but could trap more legitimate e-mail (false positives). If the server filters legitimate e-mail, users don’t know about it.
The Junk Mail Messages Should Be pop-up menu gives you four choices:
Bounced: Sends the message back to the sender. This setting usually doesn’t help and could invite a malicious attack. With this setting, you have the option of sending a notification to an e-mail address.
Deleted: Saves hard drive space but eliminates the possibility of ever retrieving false positives. This setting also gives you the option to send a notification to an e-mail address.
Delivered: Delivers the message to the user with a warning in the Subject line (such as ***JUNK MAIL***). This setting lets the user look through it for false positives. You can also encode the message as an attachment for extra security.
Redirected: Sends the e-mail to another address. This could be an address for an administrator, who could look through it for false positives. The downside is that it takes a lot of hard drive space, given the flood of spam that everyone gets.
You can also block all e-mail from a known spam server. In the left column of Server Admin, under your server, click Mail, click the Settings icon in the toolbar, and then click the Relay tab. You can then type the IP addresses of one or more known spammers.
Spam-filtering exceptions by country or language
Below the slider in the Server Admin spam and virus filter window are settings for accepted languages and locales. For example, the spam filter often categorizes all e-mail with non-roman typefaces as junk mail.
If you routinely get legitimate e-mail in the Korean language, you can use the Accepted Locales setting to enable e-mail with a Korean country code to get through. The Accepted Languages list lets through e-mail written in different specific languages that you might receive.
Click the pencil icon to bring up a new window for selecting additional languages or locales.
The Enable Virus Filtering setting looks at e-mail by using a different method from the one it uses for spam. It uses the open source ClamAV software to keep track of known malicious e-mail viruses, worms, and other malware and is automatically updated regularly. You can set how often the virus database is updated in the Update the Virus Databases box at the bottom of the window.
You can tell the server what to do with the virus e-mail in the Infected Messages Should Be pop-up menu. You get three options:
Bounced: The Bounced setting usually doesn’t help and may invite a malicious attack.
Deleted: Lets you notify the user or any e-mail address that a suspected virus has been deleted. Most people should use this setting.
Redirected: Sends the suspected infected e-mail to an e-mail address.