As many are already aware, Microsoft and other industry leaders introduced sender ID filtering to assist in the combat against e-mail spam. Basically the concept of sender ID filtering is to verify that the host sending the email is authorized to send email for that domain. With sender ID filtering enabled, the receiving server will check the “mail from” domain’s SPF record to retrieve a list of valid senders for that domain. To learn more about the Sender Policy Framework please see the following document. http://www.microsoft.com/downloads/details.aspx?familyid=D8A174B1-697C-4AEA-9C92-2E70A013C30B&displaylang=en.
The “Setup Your Internet Address” wizard in SBS 2008 can configure your SPF record for you if you selected for SBS 2008 to manage your DNS records. An SPF record is a basic “TXT” record in DNS, which in SBS is configured as v=spf1 a mx ~all. Here is a breakdown of what each portion defines[…]