You are the messaging engineer for your company. All user mailboxes are hosted on Exchange Server 2003 servers. You do not plan to move any mailboxes to the Exchange Server 2007 Mailbox servers or to upgrade your Active Directory schema. You need to recommend a solution that uses Exchange Server 2007 to reduce the amount of spam that enters the Exchange organization. Which two of the following solutions should you recommend? (Each correct answer presents a complete solution. Choose two.)