Spam Filter Settings

Sonora Communications, Inc.

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Spam Filter Settings

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Mail Server

Our SonoraMail mail server offers state of the art performance and security with the latest anti-malware features.  We also provide simple, fast webmail access to your mailbox from any PC with a browser.

Secure, encrypted connections are forced for your security.

Spam and Malware Filters

We use the popular SpamAssassin spam filtering software and the Clam Antivirus malware scanner software.

We have also implemented Greylisting. Greylisting is a very useful spam-fighting technique where incoming messages are compared against a database of previously-received messages.  If the sender is not on the list, the mail server refuses the incoming message with a soft error telling the sending server to try back later. This works incredibly well because most spammers will just move on and will not 'try back later' whereas all valid mail servers will.  The downside is that the first message from any sender is delayed by at least one minute.

Our recent server and software upgrades provide:

  • Individual Users
    • more mail configuration options
    • more spam filtering preferences
    • etc.
  • Domain Owners
    • more web site configuration options
    • more user management options
    • better disk quota management
    • domain-wide filtering preferences
    • etc.

Mail users can set their individual mail preferences using a web browser by logging into their webmail.  There are a great number of mail preference settings, but here we discuss spam-related settings only.

How to Set Your Webmail Spam Options

Webmail Logon

Log in with your regular e-mail user name and password.

Click Mail Preferences.

Once in Mail Preferences, click the drop-box and select Spam options.

If you use webmail very much, you might want to experiment with these settings as they have the potential to make your life easier.  If you rarely use webmail, these settings won't matter much.

How to Set Your SpamAssassin Preferences

Next, we present two different ways to configure your spam filtering. Choose one or the other methods...not both.

The Easy Way

Do this if you are in a hurry or just want 'easy'. These filter settings are really easy to set up and quite good about getting rid of junk e-mail.

You can review your 'spam' (quarantine) folder for false-positives (falsely-filtered mail) using webmail or any IMAP mail client.

Once logged in as per above, click Usermin in the upper-left corner.

Then click Mail -> SpamAssassin Mail Filter.

The most fundamental setting is in Spam Classification.  This is where you tell the filter how aggressively you want it to act.  You probably don't want to tinker with the other settings here unless you know what you are doing.

The default classification level is 5.0.  We find that this level is fairly good at blocking spam and almost never filters valid mail (false-positive). However, you may see a bit more junk make it into your Inbox than with a more aggressive (smaller number) setting.

Setting the classification level to 4.0 is slightly more aggressive. Many users find 4.0 eliminates almost all junk with virtually no false-positives.  Be sure to check your 'junk' folder after changing this setting to look for false-positives.

Strict Filtering with More Control

(not yet updated beyond this point)

If you want more accurate filtering, or if you want a quarantine to be able to check for false-positives, try these settings in conjunction with a client-side filtering rule to route marked spam into a 'Junk' folder:

Client-Side Quarantine

These settings will prepend the e-mail message subject with ***SPAM*** or any other marker you choose.

Don't forget to create a rule in your mail client (Outlook, Thunderbird, etc.) to route all messages marked as ***SPAM*** into the junk mail folder of your choice (you may have to create one).

This gives you the benefit of more-strict spam filtering (lower 'Spam Hits' required = more strict) as well as a quarantine where you can check for falsely-filtered mail.

Creating a Client-Side Filter Rule - Outlook 2003

Tools -> Rules and Alerts -> New Rule -> Start From a Blank Rule ->

Check Messages When They Arrive -> Next -> with Specific Words in the Subject ->

Specific Words -> ***SPAM*** -> Add -> OK -> Next -> to a Folder ->

move to specified folder -> Junk E-mail -> Next -> Finish -> Run Rules Now -> Finish

Creating client-side rules varies from mail client to mail client (and even within Outlook 2003!), but they are usually similar in their setup and operation to this example.

Last Updated on Thursday, 21 October 2010 11:56