If the server is shipped in a rack, it must be supported by shipping brackets.
If the server is shipped to you in a rack, you must remove the shipping brackets before placing it in service. See How to Remove the Standard Rack Mounting Kit Shipping Brackets .
If you plan to ship the server in a rack, see How to Install the Standard Rack Mounting Kit Shipping Brackets.
The shipping bracket parts are in the accessory tray with the rack mounting hardware. See Location of the Rack Mounting Kit and the Shipping Bracket Kit for details.