ReuseSocket is a TIdReuseSocket property that indicates if socket IP addresses and port numbers can be reused for TIdListenerThread instances used in the server. ReuseSocket is used when setting the socket options for an allocated socket handle in a listener thread during server startup. 

The default value for ReuseSocket is rsOSDependent as assigned during component streaming, and indicates that socket handle reuse is dependent on the platform or Operating System hosting the Indy library.

TIdListenerThread