Enter the maximum size of email messages, in bytes, that the FortiMail unit will scan for spam. Messages larger than the set size are not scanned for spam.

To disable the size limit, causing all messages to be scanned, regardless of size, enter 0.

Note: Resource requirements for scanning messages increase with the size of the email message. If the spam you receive tends not to be smaller than a certain size, consider limiting antispam scanning to messages under this size to improve performance.

Enable to bypass spam scanning for authenticated SMTP connections.

Note: If you can trust that authenticating SMTP clients are not a source of spam, consider enabling this option to improve performance.

Spammers may attach a PDF file to an otherwise empty message to get their email messages past spam safeguards. The PDF file contains the spam information. Since the message body contains no text, antispam scanners cannot determine if the message is spam.

Enable this option to use the heuristic, banned word, and image spam scans to inspect the first page of PDF attachments.

This option applies only if you have enabled and configured heuristic, banned word, and/or image spam scans. For information on configuring those scans, see “Configuring heuristic options”, “Configuring banned word options”, and “Configuring image spam options”.

Select this option to take the default antispam action right away without applying other antispam filters if the email matches the relevant IP or recipient policy.