The NetWare Core Protocol (NCP) is a network protocol used in some products from Novell, Inc. It is usually associated with the client-server operating system

Novell NetWare NetWare is a discontinued computer network operating system developed by Novell, Inc. It initially used cooperative multitasking to run various services on a personal computer, using the Internetwork Packet Exchange, IPX network protocol. The f ...

which originally supported primarily

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few op ...

client stations, but later support for other platforms such as

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

, the

classic Mac OS Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Mac (computer), Macintosh family of personal computers by Apple Computer, Inc. from 1984 to 2001, starting with System 1 and end ...

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

Windows NT Windows NT is a Proprietary software, proprietary Graphical user interface, graphical operating system produced by Microsoft as part of its Windows product line, the first version of which, Windows NT 3.1, was released on July 27, 1993. Original ...

Mac OS X macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

, and various flavors of

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

was added. The NCP is used to access file, print, directory,

clock synchronization Clock synchronization is a topic in computer science and engineering that aims to coordinate otherwise independent clocks. Even when initially set accurately, real clocks will differ after some amount of time due to clock drift, caused by clocks ...

, messaging, remote command execution and other network service functions. It originally took advantage of an easy network configuration and small

memory footprint Memory footprint refers to the amount of main memory that a program uses or references while running. The word footprint generally refers to the extent of physical dimensions that an object occupies, giving a sense of its size. In computing, t ...

of the IPX/SPX protocol stack. Since 1991 the

TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are ...

implementation is available., page 6 Novell eDirectory uses NCP for synchronizing data changes between the servers in a

directory service In computing, a directory service or name service maps the names of network resources to their respective network addresses. It is a shared information infrastructure for locating, managing, administering and organizing everyday items and network ...

tree.

Technical information

The original IPX/SPX server implementation was provided only for

platform and now is obsolete. The

implementation uses TCP/ UDP port 524 and relies on SLP for name resolution. For NCP operation in IPX/SPX networks the bare IPX protocol was used with Packet Type field set to 17. On the workstation (client station) side the IPX socket number of 0x4003 was used, on the server side the socket number of 0x0451. The NCP PDU has the following structure: The NCP Type field determines the type of operation: Individual requests are identified by the Sequence Number (modulo 256). The Connection Number identifies an individual client station connection on the server. Novell Netware servers of version up to 2.x supported up to 255 connections and the Connection Number occupied only 1 octet. Later it was extended to 2 octets. Task number has value 3 in requests and 1 in replies. The Data field starts with NCP Function number octet which distinguishes individual services. The contents and the length of the rest of the Data field depends on the NCP Function.

Client-side implementations

Novell Client for Windows Vista
from Novell.

from Novell.

from Novell.

from Novell.

from Novell - no longer supported.
NetWare Client for Mac OS X
from Prosoft Engineering.
ncpfs
an open-source NCP client implementation for

. * Client Service for NetWare from

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

References

External links

NCP specification
without description of underlying Netware RPC framework
Wireshark (an open source protocol analyzer) Documentation - Fields of the NCP packet

{{File systems Network file systems Network protocols Novell NetWare Presentation layer protocols