CRM 2011: Limited/reduced functionality of Sandboxed plug-ins

Microsoft recommends running plug-ins in a sandbox mode. The plug-ins running in a sandboxed environment have reduced functionality to ensure security.

The following network access restrictions apply to this sandbox capability.

• Only HTTP and HTTPS protocols are allowed.
• Access to localhost is not permitted.
• Plug-ins must rely on DNS name resolution (using a named web address).
• Anonymous authentication is recommended and supported by Microsoft.
• .NET framework classes can be used in the plug-in code to access web resources considering previously outlined restrictions.

Refer to Microsoft's documentation for further information.