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Knowledgebase: Spam/Email Filters
Prevent Spam From Forwarding to External Networks
Posted on 02 June 2009 03:11 PM
Question:

I have an email alias that is set to forward email to my Yahoo account. How do I prevent it from forwarding the spam I receive?

Answer:

Enabling SpamAssassin on email addresses that forward to external networks (such as Yahoo, Hotmail, your ISP, or other email address not hosted by FutureQuest) can help to prevent spam from being forwarded to those networks and avoid the blocking that can occur as a result.

For this purpose, the two settings you'll want to focus on are to either have SpamAssassin
  • Delete the suspected spam
  • or to
  • Redirect the spam to a local POP mailbox on your domain
(The setting of Tag Only isn't appropriate here as it would still result in sending the spam on to the external network.)

With SpamAssassin, there are two filtering choices. You can implement a filter as a Global filter, which means that every mailbox under the domain will use one set of selections. Or, you can implement SpamAssassin as an Individual filter on each email account, which means you can have different settings applied to different email accounts. The Individual option allows you to apply the settings used for one email account to other email accounts as well, while also providing the option to exclude some email accounts from using those settings.

To get started on setting up SpamAssassin, you'll need to log in to your CNC and visit the Email Manager section. Then follow the instructions below, depending on how you wish to have SpamAssassin set up.


To set SpamAssassin as a Global filter to Delete suspected spam:

Under "Global Email Filters:" on your CNC's Email Manager screen, click on "SpamAssassin".

The page that follows is where you will configure SpamAssassin.

The first selection you will need to make will be to choose "Enable".

Then you'll choose "Delete: All email tagged as spam will be deleted and cannot be retrieved later".

Scroll down the page and press the "Save Settings" button. As you chose to Delete messages tagged as spam, you will be presented with a warning that all mail deleted as a result of this filter cannot be recovered. Click on "Confirm" to complete the filter setup.


To set SpamAssassin as an Individual filter to Delete suspected spam:

From the main CNC Email Manager screen, click on the email username for which you wish to enable SpamAssassin.

Then in the next page, you should see "SpamAssassin Filter: No [edit]". Click on 'edit'.

The first selection you will need to make will be to choose "Enable".

Then you'll choose "Delete: All email tagged as spam will be deleted and cannot be retrieved later".

Scroll down the page, past the "Save Settings" button, and you'll see a list of all your email addresses. Place a tick next to every email alias and POP mailbox you want this filter to be enabled on, then click the "Save Settings" button.

As you chose to Delete messages tagged as spam, you will be presented with a warning that all mail deleted as a result of this filter cannot be recovered. Click on "Confirm" to complete the filter setup.


To set SpamAssassin as an Individual filter to Redirect suspected spam to a POP mailbox:

This option is for those who wish to review messages that are tagged as spam prior to deleting them to ensure that no valid messages are inadvertently tagged as spam.

First, you'll need to create a POP mailbox specifically for all of the spam messages to be redirected to. (You might want to call this "junk" or "spam" to help you recognize it.)

Global SpamAssassin must be disabled prior to the following steps.

After that's done, from the main CNC Email Manager screen, click on an email username that you wish to set SpamAssassin on.

On the next page, you should see "SpamAssassin Filter: No [edit]". Click on 'edit'.

Select "Enable" to turn SpamAssassin on and then tick "Redirect: All email tagged as spam will be redirected to an address of your choice."

Then in the text field next to "If Redirect, email address to forward to:", enter the POP email address you created specifically for the spam messages.

Scroll down the page, past the "Save Settings" button, and you'll see a list of all your email addresses. Place a tick next to every email alias and POP mailbox you want this filter to be enabled on, being sure not to select the spam POP mailbox you created, then click the "Save Settings" button.

This will allow all messages that are tagged as spam to be redirected to the special POP mailbox you created and occasionally you can access that mailbox (many access a mailbox such as this from QuestMail), review the tagged messages, and then delete them. All mail saved on the server does count against your disk space and failure to access this mailbox routinely and delete the mail may result in exceeding your hosting package disk space allocation.


Note: The default scoring for SpamAssassin is set at 5.1 and is usually a good starting point. However, if you find that too many spam messages are not being captured, then lowering the score should result in more spam being tagged.

More information regarding SpamAssassin can be found within the Helpful Hints of the CNC and also at:
Email Filters - An Overview