779 Unassigned - System Port

779 is a System Port. Transport Protocol , 779 Service Name , Service Name Description: Unassigned.

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

Port	Service Name	Description
957		Unassigned
1047	neod1	Sun's NEO Object Request Broker
1615	netbill-auth	NetBill Authorization Server
1778	prodigy-intrnet	prodigy-internet
2573	trustestablish	Trust Establish
2830	silkp2	silkp2
4188	vatata	Vatata Peer to Peer Protocol
4349	fsportmap	File System Port Map
4586		Unassigned
5397	stresstester	StressTester(tm) Injector

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