What are cage nuts and rails?

• A. A security mechanism for preventing rack theft.
• B. Hardware to mount servers in square-hole racks and support their weight safely.
• C. A type of server cooling fan.
• D. A fiber patch panel.

Answer: (B)

Cage nuts and rails are mounting hardware used to install equipment in 19-inch server racks. The cage nut is a spring-loaded nut that fits into a square hole in the rack rail and provides a threaded receptacle so screws can fasten a server to the rack. Rails are the front-to-back supports that attach to the rack posts, giving a secure mounting surface at the correct depth and bearing the server’s weight so it can be slid in and out for maintenance. Together they allow mounting servers in square-hole racks safely. They are not a security mechanism, a cooling fan, or a fiber patch panel.