Mailshell 101

Just downloaded a copy of Mailshell from TechSoup? We'll help you get started with this popular anti-spam tool by showing you a few how-tos for installing and configuring it on your computer, including how to set up Mailshell to work with Microsoft Outlook and how to tailor Mailshell to your spam-filtering needs.

Have additional questions about Mailshell? Visit our Mailshell Product Resource Page. For general advice about fighting spam, see TechSoup's Spam Prevention Toolkit.

1. Integrate Mailshell Outlook Edition with Microsoft Outlook.

Integrate Mailshell Outlook Edition with your Microsoft Outlook email client by following the steps below.

If you have yet to install Mailshell or are about to try again:

You may increase your chances of a smooth installation by following these tips:

1. Ensure that your computer setup meets Mailshell's minimum system requirements.
2. Ensure that your copy of Microsoft Outlook is licensed and has the latest patches and updates installed. Novice users should check with their organization's IT person or a technical user. Advanced users can check for updates at Microsoft's Office website.
3. Make sure that all programs — including Outlook — are closed before you attempt to install Mailshell.

If you previously installed a Mailshell SpamCatcher program on your computer and then later uninstalled it:

The Mailshell uninstall process may have left behind Windows registry information that could affect your new installation. Before you install your new version of Mailshell, you should check your registry for the following keys and delete them:

HKEY_LOCAL_MACHINE\SOFTWARE\Mailshell *

Note that modifying your Windows registry is recommended for advanced Windows users and IT personnel only. Always back up your registry before modifying it in case you need to recover from a mistake.

If, after installing Mailshell and first launching Outlook, you do not see a dialog box that prompts you to enter your registration code, or, if after entering your registration code, Mailshell does not prompt you to choose or create a folder where you want it to direct suspected junk mail:

First, shut down Outlook; then restart it. Look for the registration prompt. If you see the prompt, enter your registration code and proceed to use Mailshell.

If you don't get a prompt, shut down Outlook and restart your computer. Launch Outlook again, right-click in an empty part of the menu bar, and see if Spamcatcher is listed in the pop-up menu. If it is there and unchecked, check it and proceed to use Mailshell. If it is not there, follow these steps.

1. Choose Help > About Microsoft Office Outlook.
2. Click Disabled Items.
3. Select Mailshell AntiSpam and click Enable.

If you see a message about invalid email keys:

If there is a message about email keys, send email to TechSoup Customer Service with the subject Invalid Mailshell Keys.

2. Prevent Outlook from crashing or freezing.

If you are also running McAfee VirusScan Professional Edition on your computer while you use Mailshell:

Mailshell's documentation notes a known issue in which the program may crash on computers running McAfee VirusScan Professional Edition. To correct this problem, Mailshell suggests disabling McAfee VirusScan's HAWK Script Stopper.

1. First, shut down Outlook.
2. Open VirusScan's main interface.
3. To the left side of VirusScan's interface, find the option labeled Configure Automatic Protection Settings.
4. Uncheck Enable HAWK Script Stopper and click Apply Settings.
5. Finally, relaunch Outlook.

If disabling the HAWK Script Stopper has no effect or your computer is not running McAfee VirusScan:

Try completely uninstalling and reinstalling Mailshell.

1. In your Windows Start menu, choose Start > Settings > Control Panel > Add or Remove Programs.
2. Scroll down the list and find an entry called "Mailshell Anti-spam Outlook Addin."
3. Click the Mailshell entry and then click Remove.

After Mailshell uninstalls, restart your computer; then reinstall the program.

3. Adjust your filter settings.

Mailshell Universal Edition and Mailshell for Outlook Edition use a combination of different filtering methods to identify and block spam. Depending on your needs, you can adjust some of its filter settings to increase the level of protection.

Set Spam Filter to More Aggressive

By default, Mailshell is configured with a more lenient setting. While this decreases the chance that legitimate emails will be filtered to your spam folder, it also means that more spam might make it to your inbox. However, you can easily configure the filter to take a more aggressive approach to spam.

If you're using Mailshell Anti-Spam Universal Edition, click the program's system-tray icon — the small yellow circle with a white envelope that appears in the lower-right corner of your screen. Click the option called Enable Spam Flagging. To the right side of the interface, you'll see a bar and a slider; drag the slider left toward the side of the bar labeled More Aggressive and click Apply. If you find that the program is still letting too much spam through, configure it to be even more aggressive by dragging the slider further to the left.

If you're using Mailshell Anti-Spam Outlook Edition, find the application's Outlook toolbar (located near the email client's upper-left corner) and click the icon labeled "Mailshell." Next, choose Settings > Enable Custom Spam Filter Strength and check the box next to this option. To the right side of the interface, you'll see a bar and a slider; drag the slider left toward the side of the bar labeled More Aggressive and click OK. If you find that the program is still letting too much spam through, configure it to be even more aggressive by dragging the slider further to the left.

Enable the Real-Time Blacklists

Mailshell offers to check incoming messages against eight real-time blacklists (RBLs), which are publicly available lists of known and suspected spammers maintained by third parties. Enabling this option — which is not turned on by default — ensures that Mailshell will block messages from any email or IP addresses found on those lists.

If you're using Mailshell Anti-Spam Universal Edition, click the program's system-tray icon and choose Public Blacklists (RBLs). To the right side of the interface, you'll see eight RBLs with checkboxes. Check the boxes next to all of the RBLs and click Apply.

If you're using Mailshell Anti-Spam Outlook Edition, click Mailshell on the Outlook toolbar. Next, choose Settings > Public Blacklists (RBLs). To the right side of the interface, you'll see eight RBLs with checkboxes. Check the boxes next to all of the RBLs and click OK.

Enable and Train the Bayesian Filter

Mailshell also fights spam using a Bayesian filter, a system that theoretically becomes more effective the longer you use it. But in order for a Bayesian filter to work well, you must first "train" it by regularly marking messages as spam or legitimate emails. In this way, the filter learns what messages each individual user considers undesirable and applies this logic to future emails. Therefore, it may take some time and effort before a Bayesian filter performs well.

To enable the Bayesian filter in Mailshell Universal Edition, click the system-tray icon and choose Enable Word Training. If this box is unchecked, check it and click Apply. You can also increase the strength of the Bayesian filter by typing a larger number in the field labeled Maximum Number of Word Entries, though Mailshell's documentation explains that this will cause the program to use more memory. Once Mailshell's Bayesian filter has been trained and seems to be working well, you might also want to set its Training Weight to high, which will configure the program to rely more heavily on the Bayesian filter than on its other methods.

To enable the Bayesian filter in Mailshell Outlook Edition, click Mailshell on the Outlook toolbar. Next, choose Settings > Enable Word Training. If this box is unchecked, check it and then click OK. You can also increase the strength of the Bayesian filter by typing a larger number in the field labeled Maximum Number of Word Entries, though Mailshell's documentation explains that this will cause the program to use more memory. Once Mailshell's Bayesian filter has been trained and seems to be working well, you might also want to set its Training Weight to high, which will configure the program to rely more heavily on the Bayesian filter than its other methods.

For more information on different spam-filtering techniques, read TechSoup's article Ten Spam-Filtering Methods Explained.

4. Increase email-delivery speeds.

Some Mailshell users have stated that the application delays mail delivery while it determines whether incoming messages are legitimate or spam. Adjusting a few of the program's settings may increase email delivery speeds, though doing so may adversely affect the amount of spam that Mailshell detects.

Disable Rules-Based Spam Filtering

In addition to the other methods, Mailshell uses rules-based, or "heuristic," filtering to help weed out spam. Because heuristic filters must scan the contents of each message and tally a final score to decide whether the email should be classified as spam, enabling this feature can slow down delivery times.

To disable rules in Mailshell Universal Edition, click the system-tray icon and choose Enable Rules. Uncheck the box and click Apply.

To disable rules in Mailshell Outlook Edition, click Mailshell. Next, choose Settings > Enable Rules. Uncheck the box and click OK.

If you find that disabling Mailshell's rules leads to an increase in spam without significantly increasing delivery speeds, you may want to eventually re-enable this option to provide an extra layer of spam protection.

Adjust Real-Time Blacklist (RBL) Settings

Mailshell can check incoming emails against publicly available lists of known and suspected spammers. But checking these lists can take time. Adjusting a few of Mailshell's RBL settings in favor of fewer checks might help to speed up mail delivery.

For instance, Mailshell allows you to check your email against multiple blacklists. But if you're confident that the results from using just one blacklist is sufficient for identifying spam, then you can disable the option. The option is labeled Enable RBL MultiHit.

Mailshell also uses RBLs to check whether your email was sent through certain servers known for being spam outlets. The Internet Protocol (IP) addresses for these servers are saved in the email "envelope." By limiting the maximum number of IP addresses that Mailshell checks for each message, you may be able to save time. This option is labeled as Maximum Number of IPs to Query Against RBLs.

To access the RBL settings if you're using Mailshell Universal Edition, click the system-tray icon and choose RBL Expert Options.

To access the RBL settings if you're using Mailshell Outlook Edition, click Mailshell on the Outlook toolbar. Next, choose Settings > RBL Expert Options.