How to Block Spam Using Plesk

A few months ago, I’ve made a post about SpamAssassin, a great free antispam tool. In fact, cPanel uses SpamAssassin to block unwanted mails.

This time around, we’ll see how to block spam using Plesk. While its spam filter management interface is different than cPanel, it’s still quite easy to use.

For this tutorial, I’ll be using my FatCow account so your Plesk control panel may differ a little bit from mine.

1. Log in to your Plesk control panel.
2. In the E-Mail section, click the Manage Spam Filter icon.
   
3. Enable spam filtering by clicking the Yes radio button.
   
4. Select the Handling Option best suited to your needs.
   
5. Click the Save Spam Management Settings button.
   

Greylisting and Auto Whitelisting

Greylisting is an email blocking mechanism where messages are first rejected with a “temporary rejection” message. If the message is resent within a specified amount of time, the email is accepted.

Greylisting works because most spammers do not resend rejected messages (or check to see if messages are rejected, for that matter) and legitimate (i.e., non-spam) email servers will try to resend the message.

If the message is retried, it is successfully delivered and is automatically added to the user’s whitelist and does not have to go through the greylisting process again.

To enable greylisting and auto whitelisting:

1. Select a domain to enable greylisting or auto whitelisting. Click the Go button if you changed the default selection.
   
2. Select Yes on each option to enable greylisting and auto whitelisting.
   
3. Click the Save Greylist Settings button to save your changes.
   

Whitelist and Blacklist Email

Whitelisted email addresses are always accepted. Blacklisted email addresses are always rejected. Simple as that.

Plesk allows you to set up whitelist and blacklist addresses, entire domains, or by Class C IP addresses.

To add whitelist or blacklist entries :

1. Select a domain.
   
2. Select whitelist or blacklist.
   
3. Select a recipient from the drop-down list:
   
4. Enter a sender’s email address or domain in the Sender text box. Entering * will cause ALL messages to be filtered.
   
5. Add a specific IP address. *.*.*.* will cause messages from the Sender at any IP address to be filtered.
   
6. Click the Save Entry to List button.
   
7. The page will refresh and provide an Entry Added notification if the entry was successful.
   
8. At the bottom of the page, your new entry will be displayed in a table. Click the Delete link to delete the filter.
   

So as you can see, using Plesk’s Spam Filter isn’t that complicated, but remember to be careful not lose some legitimate emails in the process.