Spam and virus filtering is enhanced by or is also available as a service from Microsoft Exchange Hosted Services. Exchange Hosted Services is a set of four distinct hosted services:

• Hosted Filtering, which helps organizations protect themselves from e-mail-borne malware.
  
• Hosted Archive, which helps organizations satisfy retention requirements for compliance.
  
• Hosted Encryption, which helps organizations encrypt data to preserve confidentiality.
  
• Hosted Continuity, which helps organizations preserve access to e-mail during and after emergency situations.
  

These services integrate with any on-premise Exchange servers that are managed in-house or Hosted Exchange e-mail services that are offered through service providers.