Setting up Spamassassin - The Basics

You'll need to be logged into the Squirrelmail webmail interface to set up Spamassassin (though Spamassassin will work on all incoming mail regardless of where you're reading it, Squirrelmail is currently the only web-based option for configuring it). Go into Options->Spamassassin.

Here, you'll see a set of tables. The one you'll start with is General Settings, which contains the following options:

• Use Filtering. Place a checkmark in this box to en able Spamassassin.
• Required Hits. As mentioned earlier, Spamassassin works by running a series of tests against a message, computing a total score based on positive test results, and filtering messages which score above a given threshold. This is where you set that threshold. The default is 5; this is still rather permissive, so you may want to lower it a bit. Remember that lowering this number will increase the amount of mail that gets marked as spam, and increases the chance of false positives.
• Rewrite Subject. If Spamassassin filters a message , this setting will add "****SPAM****" to the subject. This is enabled by default.
• Defang Mime. Contrary to what you might expect, th is setting has no effect on the lethality of silent clowns. MIME ("Multipurpose Internet Mail Extensions") is a set of specifications used for encoding non-ASCII attachments (e.g. image files, .pdfs, MS-Word files) for delivery via email. If this setting is enabled, it will render such files unreadable. This is a good thing if the attachment contains malware, but not so good if the message is mistakenly filtered, and the attachment is a document you actually need. This setting is disabled by default.
• Spam Folder. This determines where filtered spam i s delivered. It can be any of your IMAP folders, or the spam can be deleted immediately. We recommend setting it to "Trash"; mail in Trash is automatically deleted after it has been there for seven days, long enough to review for false positives. We don't recommend having setting it to "Delete Permanently" unless you are absolutely certain that you will not lose anything you want.

Immediately below General Settings is Allowable Locales, which controls

Filtering Mail by Language

Whitelisting and Blacklisting

"Manage Whitelist" and "Manage Blacklist" control, respectively, senders whose mail you always and never want to receive.

To add a sender to either list, type the address into the text field of the list you want to add it to, and click the "Add New" button. Wildcard addresses, to block entire domains, will also work.

Although it might make sense to use the Blacklist against spam addresses, and although this may even work against some, this is sadly not a practical strategy. More often than not, spam originates from forged or disposable addresses, and blacklisting will either not work against them at all, or will only do so temporarily. The Blacklist is more effectively deployed against specific sources of (for example) harrassment.

Customizing Spam Rules

This section will, for most users, be completely optional.

Under Manage Spam Rules, you can set new scores for specific tests run by Spamassassin, should you find that their default scoring is too aggressive or not aggressive enough. You will most likely do this in response to obvious spam which is consistently delivered to your Inbox after triggering certain tests (the tests triggered will be visible in the messages "X-Spam-Status:" header).