There is no difference in the installer for Xeams Community and Enterprise Edition. It will run as if you have purchased the Enterprise Edition for the first 30 days. It will then get converted to Community Edition unless a license is purchased.
Oliver,
What you're referring is called a Reverse NDR attack. Click here for details. If you like you can block NDRs temporarily until this is over by enabling the Non-Delivery Report filter under Filter Management/Content Filters/Custom Filters.
