The MPF Engine servers will communicate with various back-end systems through MPF Providers. Hosted Messaging and Collaboration ships 23 providers that use varying protocols or APIs to perform actions both locally and on remote servers. A Service Provider should take steps to ensure that this communication can not be inspected, redirected, or modified by rogue users or systems. Some actions like the following should be taken:

• Configure firewalls to only allow connections between the MPF engine server and the servers in order to perform necessary provisioning actions.
• Explicitly disallow MPF Engine servers from connecting to any servers outside of your data center.
• Configure firewall rules to ensure that only the necessary protocols are open between MPF Engine and provisioned servers. The table below describes the APIs or Protocols used by each provider this may be helpful in defining firewall rules.

  Provider Name	Protocol/API	Notes
  Active Directory Provider	System.DirectoryServices
  BlockModelRMO	System.Data.SQLClient
  Command Line Provider	CreateProcess (Local Only)
  Computer Management Provider	System.DirectoryServices Native Advapi32 methods (LSA*) (interop)
  CoreRMO	System.Data.SQLClient
  DNS Provider	HTTPS (remote) WMI (local)	The DNS provider has a .NET remoting component that must be installed on each target DNS server.
  Error Provider	(Local only)
  Exchange 2007 Mobility Provider	Powershell Exchange 2007 Cmdlets
  Exchange 2007 Provider	System.DirectoryServices Powershell Exchange 2007 Cmdlets
  File System Provider	(Local Only) Various File IO and security APIs
  FrontPage Provider	System.Web.Services.Protocols
  IIS Provider	System.DirectoryServices IISOle
  Office Communications Server Provider	System.DirectoryServices WMI
  Powershell Provider	(Local Only) PowerShell
  Registry Provider	Microsoft.Win32.Registry*
  Scripting Provider	IActiveScript (Interop)
  SharePoint2007Provider	HTTPS (Remote) Microsoft.SharePoint class library (local)	The SharePoint2007 Provider has a Web Service component that must be installed on a SharePoint Server, remote MPF Engines use HTTPS to connect to this Web Service.
  SMTP Mail Provider	System.Net.Mail.SMTPClient
  SQL Admin Provider	System.Data.SQLClient
  SQL Provider	OLEDB
  Unified Messaging 2007 Provider	Powershell Exchange 2007 Cmdlets
  Windows Installer Provider	WMI
  XML File Provider	(Local Only) System.IO System.XML