Postmarking: helping the fight against SPAM
Postmarking is a new part of the Outlook 2007 junk e-mail feature; it complements the existing feature set to reduce the amount of spam in your inbox.
One of the great advantages of e-mail is that it is easy and cheap to send. Unfortunately, this is the very same reason that makes it so useful to spammers as it enables them to send huge amounts of email in bulk.
Think of Postmarking as computational “postage” imposed when sending email. This is a small burden for an individual user, but is a very large burden for spammers. Spammers rely on being able to send thousands of mails per hour, and in order to be able to send spam with postmarking turned on, they would have to invest a very large amount of money to expand their computational power.
Postmarking generation is only present in Outlook 2007 and postmark validation is present in Outlook 2007, Windows Live Mail , Exchange 2007, and Windows Mail in Vista.
So, how does it work?
Sending e-mail with postmark: Before messages leave your Outbox, Office Outlook 2007 stamps each message with an e-mail postmark. The postmark incorporates unique characteristics of the message, including the list of recipients and the time when the message was sent, making the postmark valid only for that message. As a result it takes a little longer for the message to leave the Outbox – however, this is not noticeable during normal day-to-day Outlook usage.
Receiving e-mail with a postmark: When a recipient e-mail application that supports Outlook e-mail postmarking receives postmarked mail, it recognizes the postmark. The postmark means that the message is most likely not spam and this is an additional factor evaluated by the junk e-mail filter when determining if an email is spam or not.
How to turn Postmarking off
To turn on/off Postmarking, use the following option in Outlook 2007:
1. On the Tools menu, click Options.
2. On the Preferences tab, under E-mail, click Junk E-mail.
3. Clear the When sending e-mail, postmark the message to help recipient e-mail programs distinguish regular e-mail from junk e-mail check box.
Thanks!
Alessio Roic
Outlook Program Manager
