The configuration of SPF is done from the Anti-Spam > Sender Policy Framework node. Right click on this node to open the SPF properties.
Never: Never block any messages. When this option is selected, SPF tests are not done on incoming emails.
Low: Only block messages that are determined to have a forged sender. This option will treat any message with a forged sender as spam.
Medium: Block messages which appear to have a forged sender. This option will treat any messages that appear to have a forged sender as spam. This is the default and recommended setting.
High: Block any message that is not proven to be from the sender. This option will treat all email as spam unless it could be proven that the sender is not forged. Since the majority of mail servers do not yet have an SPF record, this option is not yet recommended.
After you define the sensitivity required for your SPF test, click on the Apply button to save this configuration. If you have already specified in GFI MailEssentials that this computer is not your perimeter SMTP server (refer to ‘Defining your perimeter (gateway) SMTP server’ section in this chapter), a dialog box similar to the one shown below will pop up. This dialog box shows the perimeter SMTP server settings that you have configured in GFI MailEssentials (i.e. the IPs specified for your perimeter SMTP server).
This dialog box will remind you that if this computer is not a perimeter server, you must configure the Perimeter SMTP Servers option in the Anti-spam node properties (right click on the
Anti-Spam node and select
Properties. Click on the
Perimeter SMTP Servers tab). For further information on how to configure your perimeter SMTP server, please refer to the ‘Defining your perimeter (gateway) SMTP Server’ section in this chapter.
Click on the OK button. If you wish to test your DNS settings/services, click on the
Test button located on top of the
Apply button.
IP exception list: IP addresses in this list will automatically pass SPF checks. Click on the
Add button to add a new IP address. To remove an IP address, select it from the list and click on the
Remove button. To disable the IP exception list uncheck the
IP exception list checkbox.
Recipient exception list: With this option you can ensure that certain recipients always receive their email, even if the messages should be rejected. A recipient exception can be entered in one of three ways:
Trusted Forwarder Global Whitelist: The Trusted Forwarder Global Whitelist (www.trusted-forwarder.org) provides a global whitelist for SPF users. It provides a way of allowing legitimate email that is sent through known, trusted email forwarders from being blocked by SPF checks because the forwarders do not use some sort of envelope-from rewriting system. By default, this setting is enabled. It is recommended to leave this option enabled always.
After you have configured the SPF feature, click on the Actions tab to specify what you want to do with emails marked as Spam by the SPF filter. For more information on possible actions, please refer to the ‘Actions – what to do with spam email’ section in this chapter.
