Order Number: AA-Q06TE-TE

This manual describes concepts and planning tasks to prepare you to use the DIGITAL TCP/IP Services for OpenVMS product.

Revision Information: This is a revised manual.

Operating Systems: OpenVMS Alpha Versions 7.1, 7.2, 7.2-1 OpenVMS VAX Versions 7.1, 7.2, 7.2-1

Software Version: DIGITAL TCP/IP Services for OpenVMS Version 5.0A

Compaq Computer Corporation
Houston, Texas

Digital Equipment Corporation makes no representations that the use of its products in the manner described in this publication will not infringe on existing or future patent rights, nor do the descriptions contained in this publication imply the granting of licenses to make, use, or sell equipment or software in accordance with the description.

Possession, use, or copying of the software described in this publication is authorized only pursuant to a valid written license from Digital Equipment Corporation or an authorized sublicensor.

© Digital Equipment Corporation 1999. All rights reserved.

Compaq, the Compaq logo, and the DIGITAL logo are registered in the U.S. Patent and Trademark Office.

Alpha, AlphaServer, AlphaStation, DEC, DECnet, DIGITAL, OpenVMS, PATHWORKS, Tru64, VAX, VMS, are trademarks of Compaq Computer Corporation.

The following are third-party trademarks:

ARCnet is a registered trademark of DATAPOINT Corporation.

JOIN is a trademark of Competitive Automation, Inc.

MS-DOS is a registered trademark of Microsoft Corporation.

NetBIOS is a trademark of Micro Computer Systems, Inc.

NFS, PC-NFS, and Sun are registered trademarks of Sun Microsystems, Inc.

OSF/1 is a registered trademark of The Open Group.

PostScript is a registered trademark of Adobe Systems Incorporated.

UNIX is a registered trademark in the United States and other countries, licensed exclusively through The Open Group.

X Window System is a trademark of Massachusetts Institute of Technology.

Windows NT is a registered trademark of Microsoft Corporation.

All other trademarks and registered trademarks are the property of their respective holders.

ZK6523

This document is available on CD-ROM.

Contents

Index

An open communications standard defined by the worldwide networking community, TCP/IP consists of numerous application, routing, transport, and network management protocols. These protocols enable any connected host to communicate with any other connected host, without needing to know details about the other host or the intervening network topology. Computers and networks from different manufacturers running different operating systems can interoperate seamlessly.

The DIGITAL TCP/IP Services for OpenVMS product is Compaq's implementation of the TCP/IP networking protocol suite and internet services for OpenVMS Alpha and OpenVMS VAX systems.

This manual introduces the TCP/IP Services product and provides conceptual and planning information to help you configure and manage the product.

Intended Audience

This manual is for anyone who needs an overview of the TCP/IP Services product.

See the DIGITAL TCP/IP Services for OpenVMS User's Guide for information on using TCP/IP Services applications and the DIGITAL TCP/IP Services for OpenVMS Management guide for details on configuring and managing the TCP/IP Services product.

Document Structure

This manual contains the following chapters, appendixes, and a glossary.

• Chapter 1 provides an overview of the TCP/IP Services product.
• Chapter 2 introduces TCP/IP networking concepts.
• Chapter 3 describes the TCP/IP Services implementation of the Berkeley Internet Name Domain (BIND) service.
• Chapter 4 describes the Network File System (NFS) and the differences between OpenVMS and the UNIX style file systems.
• Chapter 5 describes general planning issues to consider before configuring your system to use DIGITAL TCP/IP Services for OpenVMS.
• Appendix A describes how to register your network with a network registry and your domain and name servers with your parent-top-level domain.
• Appendix B lists the RFCs associated with the TCP/IP Services for OpenVMS implementation.
• Appendix C provides worksheets for use when configuring your system.
• The Glossary provides a glossary of terms.

Guide to Documentation

Table 1 lists the the documents available to you with this version of DIGITAL TCP/IP Services for OpenVMS.

Table 1 DIGITAL TCP/IP Services for OpenVMS Documentation

Manual	Contents
DIGITAL TCP/IP Services for OpenVMS Concepts and Planning	This manual introduces the TCP/IP Services product and provides conceptual and planning information to help you configure and manage the product. This manual also provides a glossary of terms and acronyms, lists the RFCs associated with this product, and documents how to register your network and domain and name servers.
DIGITAL TCP/IP Services for OpenVMS Release Notes	This text file describes new features and changes to the software including installation, upgrade, configuration, and compatibility information. These notes also describe new and existing software problems and restrictions, and software and documentation corrections. Print this text file at the beginning of the installation procedure and read it before you install DIGITAL TCP/IP Services for OpenVMS.
DIGITAL TCP/IP Services for OpenVMS Installation and Configuration	This manual explains how to install and configure the DIGITAL TCP/IP Services for OpenVMS layered application product.
DIGITAL TCP/IP Services for OpenVMS User's Guide	This manual describes how to use the applications available with DIGITAL TCP/IP Services for OpenVMS such as remote file operations, e-mail, TELNET, TN3270, and network printing. This manual also explains how to use these services to communicate with systems on private internets or on the worldwide Internet.
DIGITAL TCP/IP Services for OpenVMS Management	This manual describes how to configure and manage the DIGITAL TCP/IP Services for OpenVMS product. Use this manual with the DIGITAL TCP/IP Services for OpenVMS Management Command Reference manual.
DIGITAL TCP/IP Services for OpenVMS Management Command Reference	This manual describes the DIGITAL TCP/IP Services for OpenVMS management commands. Use this manual with the DIGITAL TCP/IP Services for OpenVMS Management manual.
DIGITAL TCP/IP Services for OpenVMS ONC RPC Programming	This manual presents an overview of high-level programming using open network computing remote procedure calls (ONC RPC). This manual also describes the RPC programming interface and how to use the RPCGEN protocol compiler to create applications.
DIGITAL TCP/IP Services for OpenVMS System Services and C Socket Programming	This manual describes how to use the OpenVMS system services and C Socket programming interfaces to develop network-based applications.
DIGITAL TCP/IP Services for OpenVMS eSNMP Programming and Reference	This manual describes the Extensible Simple Network Management Protocol (eSNMP), the eSNMP application programming interface (API), and how to build additional subagents to manage vendor-specific equipment.

For additional information about the DIGITAL TCP/IP Services for OpenVMS products and services, access the DIGITAL OpenVMS World Wide Web site at the following URL:

http://www.openvms.digital.com:8000/

If you are looking for a comprehensive overview of the TCP/IP protocol suite, you might find the following useful:

• Comer, Douglas E. Internetworking with TCP/IP Volume 1: Principles, Protocols, and Architecture. Third edition. Englewood Cliffs, NJ: Prentice-Hall Inc., 1995.
• Stevens, W. Richard. UNIX Network Programming Volume 1: Networking APIs: Sockets and XTI. Second edition. Englewood Cliffs, NJ: Prentice-Hall Inc., 1999.
• Stevens, W. Richard. UNIX Network Programming Volume 2: Interprocess Communications. Second edition. Englewood Cliffs, NJ: Prentice-Hall Inc., 1999.

Terminology

DIGITAL TCP/IP Services for OpenVMS Version 5.0 completes the change initiated several releases ago when the product name changed from "ULTRIX Connection (UCX)" to "DIGITAL TCP/IP Services for OpenVMS." To complete this change, the identifier "UCX" is replaced with "TCPIP" in the following:

• Registered product facility code
• Management command prompt
• All messages, examples, and banners
• All product file names, queues, and databases
• All logical names, except those retained for compatibility
• All associated product documentation

DIGITAL TCP/IP Services for OpenVMS is used to mean both:

• DIGITAL TCP/IP Services for OpenVMS Alpha
• DIGITAL TCP/IP Services for OpenVMS VAX

The auxiliary server is the DIGITAL TCP/IP Services for OpenVMS implementation of the UNIX internet daemon (inetd).

NFS is the DIGITAL TCP/IP Services for OpenVMS implementation of the NFS protocols, including the NFS server, the NFS client, and PC-NFS.

TN3270 is the TELNET client software that emulates IBM 3270 model terminals.

The term UNIX refers to DIGITAL UNIX operating system. DIGITAL UNIX is fully compatible with Version 4.3 and Version 4.4 of the Berkeley Software Distribution (BSD).

Host and node both mean a system connected to an internet.

The term Internet refers to the global interconnection of networks, as defined by RFC 1208, which consists of large networks using TCP/IP to provide universal connectivity, reaching the Defense Advanced Projects Research Internet, MILNET, NSFnet, CERN, and many worldwide universities, government research labs, military installations, and business enterprises.

The term intranet refers to private interconnected networks that use TCP/IP to connect together and function as one virtual network.

Acronyms

For a complete list of acronyms used throughout this and other manuals in the DIGITAL TCP/IP Services for OpenVMS documentation set, see the glossary in this manual.

Reader's Comments

Compaq welcomes your comments on this manual.

Print or edit the online form SYS$HELP:OPENVMSDOC_COMMENTS.TXT and send us your comments by:

Internet	openvmsdoc@compaq.com
Fax	603 884-0120, Attention: OSSG Documentation, ZKO3-4/U08
Mail	Compaq Computer Corporation OSSG Documentation Group, ZKO3-4/U08 110 Spit Brook Rd. Nashua, NH 03062-2698

How To Order Additional Documentation

Use the following World Wide Web address for information about how to order additional documentation:

http://www.compaq.com/openvms

To reach the OpenVMS documentation web site, click the Documentation link.

If you need help deciding which documentation best meets your needs, call 1--800--ATCOMPA.

Conventions

All IP addresses in this manual represent fictitious addresses. The following conventions apply to this manual.

Convention	Meaning
UPPERCASE TEXT	Indicates names of OpenVMS and TCP/IP Services commands, options, utilities, files, directories, hosts, and users.
lowercase special type	Indicates UNIX system output or user input, commands, options, files, directories, utilities, hosts, and users.
bold type	Indicates a new term.
italic type	Indicates a variable.
[Return]	Indicates that you press the Return or Enter key.
[Ctrl/] x	Indicates that you press the Control key while you press the key noted by x.
[ ]	In command format descriptions, indicates optional elements. The elements are separated by vertical bars (|). You can enter as many as you want.
{ }	In command format descriptions, indicates you must enter at least one listed element. The elements are separated by vertical bars (|).
...	A horizontal ellipsis in examples indicates that additional optional arguments have been omitted.
. . .	A vertical ellipsis indicates the omission of items from a code example or display example; the items are omitted because they are not important to the topic being discussed.

The DIGITAL TCP/IP Services for OpenVMS product is the OpenVMS implementation of the industry-standard TCP/IP suite of communications protocols. With TCP/IP, heterogeneous networks can interconnect, making it possible for users to connect to remote hosts in many ways:

• Network file access --- users can access files on remote hosts.
• Electronic mail --- users can exchange messages between hosts.
• Application development --- application programmers can develop TCP/IP applications for communication between local and remote hosts.
• Download and file transfer --- users can exchange files between hosts.
• User information --- users can access information about other users logged onto the local or remote host.
• Remote management --- system managers can monitor the network and applications from remote hosts.
• Remote terminal access --- users can access a remote host as if their terminal is connected directly to that host.
• Remote command execution --- users can issue commands to remote hosts.
• Remote printing --- users can send or receive print jobs to or from remote printers.
• Remote file copy --- users can copy files that reside on remote hosts.
• Remote booting --- users can provide boot information for remote hosts.

Internetworking with TCP/IP hides the hardware details of each individual network and allows computers to communicate independently of their physical network connections. TCP/IP provides both a standard transport mechanism and full-duplex, reliable, stream communication services for software applications.

The DIGITAL TCP/IP Services for OpenVMS product provides interoperability and resource sharing between OpenVMS systems, UNIX systems, and other systems that support the TCP/IP protocol suite and Sun Microsystems' Network File System (NFS). TCP/IP systems and other internet hosts share data and resources by using standard TCP/IP protocols over a number of network hardware configurations: Ethernet, Fiber Distributed Data Interface (FDDI), Token Ring, and asynchronous transfer mode (ATM).

This chapter discusses the following:

• TCP/IP Defined: Requests for Comments ( Section 1.1)
• TCP/IP Architecture ( Section 1.2)
• Data Link Layer ( Section 1.3)
• Internet Layer Protocols ( Section 1.4)
• Transport Layer Protocols ( Section 1.5)
• Application Layer ( Section 1.6)
• Management Tools and Utilities ( Section 1.7)
• Application Programming Environment ( Section 1.8)
• Application Support ( Section 1.9)

TCP/IP evolved from the U.S. Government's need to connect many different networks regardless of their hardware architecture, operating system, or subnetwork technology. The resulting internetwork needed to be able to route data between networks, tolerate routing errors, and easily add new subnetworks. From a simple four-host entity in 1969 to today's worldwide Internet connecting thousands of networks and millions of computers, TCP/IP has become the communications standard of the Internet.

TCP/IP is an open system interconnection. Although monitored by a number of organizations, no one entity owns TCP/IP; its specifications are publicly available and constantly growing as communications requirements evolve.

The process by which the specifications evolve is through a mechanism called Requests for Comments or, more commonly, RFCs. Basically, when someone has an idea for a new or improved capability for TCP/IP, he or she writes a proposal, posts it on the Internet as an Internet draft, and requests comments from the networking community. After a review and revision cycle, working code is developed and an RFC becomes a standard protocol.

RFCs are available on the Internet from an organization called the Internet Network Information Center, or InterNIC. Appendix B lists relative RFCs and explains how you can obtain copies of RFCs.

1.2 TCP/IP Architecture

The TCP/IP protocol suite is designed in a fashion similar to that of the OSI layered model. However, the TCP/IP protocol suite has four layers while the OSI model has seven layers. Figure 1-1 shows the relationship between the layers of the two models.

Figure 1-1 Relationship Between TCP/IP and OSI Models

As shown in the illustration, the OSI model's Session and Presentation layer functions are fulfilled by the TCP/IP Application layer protocols. Likewise, some of the functions of the OSI Physical layer are handled by the Network Interface layer and the hardware itself in the TCP/IP model.

Figure 1-2 and Table 1-1 outline the layers of the TCP/IP model. Sections 1.4 through 1.6 summarize the protocols.

Figure 1-2 DIGITAL TCP/IP Protocol Architecture

Table 1-1 TCP/IP Network Architecture Description

Layer	Function
Data Link	Transmits data across a single network. This layer also receives data routed from the Internet layer and transmits the data to its destination.
Internet	Moves data around the internetwork. The Internet Protocol routes packets across networks independently of the network medium. It also encapsulates datagram headers, sends ICMP error and control messages, and maps ARP address conversions.
Transport	Provides a flow of data between two hosts. The DIGITAL TCP/IP Services for OpenVMS product supports the two common transport protocols: Transmission Control Protocol (TCP) provides a reliable data flow between two hosts. User Datagram Protocol (UDP) provides a much simpler service to the Application layer than TCP but does not guarantee reliability.
Application	Handles the details of the particular application, protocol, or user command; not concerned with the movement of data across the network. The product supports the following TCP/IP applications, protocols, and user commands: Remote Computing TELNET for remote login to other hosts in the network. Remote commands: RLOGIN for remote login, RSH for remote shell capabilities, REXEC to execute commands to a remote host, and RMT/RCD to read magnetic tapes or CD-ROMs from remote hosts. Finger utility to display user information. File Transfer File Transfer Protocol (FTP) to transfer files between hosts. Trivial File Transfer Protocol (TFTP) to download and transfer files. Resource Sharing Line printer/line printer daemon (LPR/LPD) to provide printing services to local and remote hosts. TELNET Print Symbiont (TELNETSYM) to provide remote printing using the TELNET protocol. Network File System (NFS) and PC-NFS to authenticate requests and access remote files. Electronic Mail Simple Mail Transfer Protocol (SMTP) for electronic mail. Post Office Protocol (POP) for electronic mail for PC users. Network Services Simple Network Management Protocol (SNMP) to monitor and manage any network device running SNMP software across an internetwork. Network Time Protocol (NTP) to synchronize time between hosts in a TCP/IP network. Berkeley Internet Name Domain (BIND), a distributed database system, to distribute and manage host information so that hosts do not need to know the address of every other host on the internet. The Bootstrap Protocol (BOOTP) to answer bootstrap requests from remote devices. Dynamic Host Configuration Protocol (DHCP), a superset of BOOTP, to assign temporary or permanent IP addresses, subnet masks, and default gateways for both BOOTP and DHCP clients. Allows the management of network connections from a single location through a graphical user interface (GUI).