As you are probably aware, IP port numbers are 16 bit unsigned integers in the range 0 to 65535. IANA (Internet Assigned Numbers Authority) manages these port numbers. See the IANA Service Name and Transport Protocol Port Number Registry for more information. IANA specifies the range 49152 to 65535 be used for dynamic (AKA private) ports. From the above referenced document: Port numbers are assigned in various ways, based on three ranges: System Ports (0-1023), User Ports (1024-49151), and the Dynamic and/or Private Ports (49152-65535); the difference uses of these ranges is described in RFC6335. System Ports are assigned by