799 Unassigned - System Port

799 is a System Port. Transport Protocol , 799 Service Name , Service Name Description: Unassigned.

Port	Protocol	Description	Source
799		Unassigned	IANA
799	TCP UDP	Mac OS X RPC-based services, Used by NetInfo, for example	Apple.com
799	TCP UDP	Unassigned	bekkoame

Port	Service Name	Description
1594	sixtrak	sixtrak
2311	messageservice	Message Service
2339	3com-webview	3Com WebView
2559	lstp	LSTP
3336	directv-tick	Direct TV Tickers
4260	vrml-multi-use	VRML Multi User Systems
5472		Unassigned
5675	v5ua	V5UA application port
5834		Unassigned
5922		Unassigned

A port is an endpoint of communication in an operating system. While the term is also used for hardware devices, in software it is a logical construct that identifies a specific process or a type of service.

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 Well Known Ports are assigned by the IANA and on most systems can only be used by system (or root) processes or by programs executed by privileged users. Ports are used in the TCP [RFC793] to name the ends of logical connections which carry long term conversations. For the purpose of providing services to unknown callers, a service contact port is defined. This list specifies the port used by the server process as its contact port. The contact port is sometimes called the "well-known port". To the extent possible, these same port assignments are used with the UDP [RFC768]. The range for well-known ports managed by the IANA is 0-1023.
DYNAMIC AND/OR PRIVATE PORTS Registered Ports are those from 1024 through 49151.
The Dynamic and/or Private Ports are those from 49152 through 65535