SBS 2008 accept external email to internal distribution lists

http://serverfault.com/questions/24769/how-do-i-make-an-exchange-2007-distribution-list-accept-external-emails

By default, Exchange 2007 only allows authenticated users to email distribution lists. To change this:




•Open the Exchange 2007 Management Console

•Expand Recipient Configuration, then Distribution Group

•Open Properties of the group in question

•Choose the Mail Flow Settings tab

•Select "Message Delivery Restrictions" and hit Properties

•Uncheck the "require that all senders are authenticated"

You can also restrict/allow senders more granularly if you like.