Filtering order

PureMessage for Microsoft Exchange filters messages in a particular order. The default order is shown below.

This order assumes that your PureMessage for Microsoft Exchange server receives mail at the SMTP transport level and that the mail is then routed to your Exchange store.

  1. Filtering. This is done at the SMTP transport level and involves recipient validation and use of custom block lists. This rejects a significant amount of mail at the SMTP transport level.
  2. Anti-virus scanning. This relates to inbound, outbound, and internal mail.
  3. Anti-spam scanning. This relates to inbound mail only.
  4. Content filtering. This relates to inbound, outbound and internal mail.
  5. Exchange store scanning. This relates to mail in the Exchange store (such as mailboxes and public folders).

The "action" that you assign to a policy also affects the filtering order. For example, if you configure content filtering so that the action to be taken is "delete", and configure anti-virus scanning so that the action is "quarantine", the content filtering is carried out first.