< networking > A TCP or UDP port number that is automatically allocated from a predefined range by the TCP/IP stack software, typically to provide the port for the client end of a client-server communication.
BSD used ports 1024 through 4999 as ephemeral ports, though it is often desirable to increase this allocation.
http://www.ncftpd.com/ncftpd/doc/misc/ephemeral_ports.html .
(2002-10-06)