# Compaq TCP/IP Services for OpenVMS

# Guide to IPv6

Order Number: AA--RNJ3A--TE

# January 2001

This manual describes the Compaq TCP/IP Services for OpenVMS IPv6 features and how to install and configure IPv6 on your system. In addition, this manual describes changes in the socket application programming interface (API) and how to port your applications to run in an IPv6 environment.

Revision Information: This is a new manual.

Software Version: Compaq TCP/IP Services for OpenVMS Version 5.1

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

Compaq Computer Corporation Houston, Texas

© 2001 Compaq Computer Corporation

COMPAQ, VAX, VMS, and the Compaq logo Registered in U.S. Patent and Trademark Office.

OpenVMS and Tru64 are trademarks of Compaq Information Technologies Group, L.P. in the United States and other countries.

All other product names mentioned herein may be the trademarks or registered trademarks of their respective companies.

Confidential computer software. Valid license from Compaq or authorized sublicensor required for possession, use, or copying. Consistent with FAR 12.211 and 12.212, Commercial Computer Software, Computer Software Documentation, and Technical Data for Commercial Items are licensed to the U.S. Government under vendor's standard commercial license.

Compaq shall not be liable for technical or editorial errors or omissions contained herein. The information in this document is provided "as is" without warranty of any kind and is subject to change without notice. The warranties for Compaq products are set forth in the express limited warranty statements accompanying such products. Nothing herein should be construed as constituting an additional warranty.

ZK6645

This document is available on CD-ROM.

Contents

# Preface

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

TCP/IP Services provides a comprehensive suite of functions and applications that support industry-standard protocols for heterogeneous network communications and resource sharing.

This manual describes IPv6 features included in this version of TCP/IP Services. The manual covers installing and configuring your system for IPv6, changes to the socket API, and how to port your applications to run in an IPv6 environment.

# Intended Audience

This manual is for experienced OpenVMS and UNIX system managers and assumes a working knowledge of OpenVMS system management, TCP/IP networking, and TCP/IP terminology.

The manual is also for programmers who want to rewrite their applications for the IPv6 environment.

# Document Structure

This manual contains the following chapters and appendixes:

Chapter 1 | Describes the IPv6 environment, the roles of systems in this environment, the types and function of the different IPv6 addresses, and how to connect to the 6bone network.
Chapter 2 | Describes how to configure the IPv6 software.
Chapter 3 | Provides guidelines for running BIND in an IPv6 environment.
Chapter 4 | Describes the resources for monitoring IPv6 network traffic.
Chapter 5 | Describes how to solve IPv6 problems.
Chapter 6 | Describes the IPv6 additions to the socket API.
Chapter 7 | Describes how to port applications.
Appendix A | Describes the supported IPv6 RFCs.
Appendix B | Lists commands and processes supported in this version.
Appendix C | Describes deprecated functions that have been replaced by new ones.

# Related Documents

Table 1 lists the documents available with this version of TCP/IP Services.

Table 1 TCP/IP Services Documentation
Manual | Contents
--- | ---
DIGITAL TCP/IP Services for OpenVMS Concepts and Planning | This manual provides conceptual information about networking and the TCP/IP protocol including a description of the Compaq implementation of the Berkeley Internet Name Domain (BIND) service and the Network File System (NFS). It outlines general planning issues to consider before configuring your system to use the TCP/IP Services software. This manual also describes the manuals in the documentation set, provides a glossary of terms and acronyms for the TCP/IP Services software product, and documents how to contact the InterNIC Registration Service to register domains and access Requests for Comments (RFCs).
Compaq TCP/IP Services for OpenVMS Release Notes | The release notes provide version-specific information that supersedes the information in the documentation set. The features, restrictions, and corrections in this version of the software are described in the release notes. Always read the release notes before installing the software.
Compaq TCP/IP Services for OpenVMS Installation and Configuration | This manual explains how to install and configure the TCP/IP Services product.
DIGITAL TCP/IP Services for OpenVMS User's Guide | This manual describes how to use the applications available with TCP/IP Services such as remote file operations, email, TELNET, TN3270, and network printing. This manual explains how to use these services to communicate with systems on private internets or on the worldwide Internet.
Compaq TCP/IP Services for OpenVMS Management | This manual describes how to configure and manage the TCP/IP Services product. Use this manual with the Compaq TCP/IP Services for OpenVMS Management Command Reference manual.
Compaq TCP/IP Services for OpenVMS Management Command Reference | This manual describes the TCP/IP Services management commands. Use this manual with the Compaq TCP/IP Services for OpenVMS Management manual.
Compaq TCP/IP Services for OpenVMS Management Command Quick Reference Card | This reference card lists the TCP/IP management commands by component and describes the purpose of each command.
Compaq TCP/IP Services for OpenVMS UNIX Command Reference Card | This reference card contains information about commonly performed network management tasks and their corresponding TCP/IP management and Compaq Tru64 UNIX command formats.
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 RPCs). This manual also describes the RPC programming interface and how to use the RPCGEN protocol compiler to create applications.
Compaq TCP/IP Services for OpenVMS Sockets API and System Services Programming | This manual describes how to use the Sockets API and OpenVMS system services to develop network applications.
Compaq TCP/IP Services for OpenVMS SNMP Programming and Reference | This manual describes the Simple Network Management Protocol (SNMP) and the SNMP application programming interface (eSNMP). It describes the subagents provided with TCP/IP Services, utilities provided for managing subagents, and how to build your own subagents.
Compaq TCP/IP Services for OpenVMS Tuning and Troubleshooting | This manual provides information about how to isolate the causes of network problems and how to tune the TCP/IP Services software for the best performance.
Compaq TCP/IP Services for OpenVMS Guide to IPv6 | This manual describes the IPv6 environment, the roles of systems in this environment, the types and function of the different IPv6 addresses, and how to configure TCP/IP Services to access the 6bone network.

For additional information about Compaq OpenVMS products and services, access the Compaq website at the following location:

    http://www.openvms.compaq.com/

For a comprehensive overview of the TCP/IP protocol suite, you might find the book Internetworking with TCP/IP: Principles, Protocols, and Architecture, by Douglas Comer, useful.

# Reader's Comments

Compaq welcomes your comments on this manual. Please send comments to either of the following addresses:

Internet | openvmsdoc@compaq.com
Mail | Compaq Computer Corporation OSSG Documentation Group, ZKO3-4/U08 110 Spit Brook Rd. Nashua, NH 03062-2698

# How to Order Additional Documentation

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

    http://www.openvms.compaq.com/

If you need help deciding which documentation best meets your needs, call 800-282-6672.

# Conventions

The name TCP/IP Services means both:

- Compaq TCP/IP Services for OpenVMS Alpha
- Compaq TCP/IP Services for OpenVMS VAX

The name UNIX refers to the Compaq Tru64 UNIX operating system.

The following conventions are used in this manual. In addition, please note that all IP addresses are fictitious.

Ctrl/ x | A sequence such as Ctrl/ x indicates that you must hold down the key labeled Ctrl while you press another key or a pointing device button.
PF1 x | A sequence such as PF1 x indicates that you must first press and release the key labeled PF1 and then press and release another key or a pointing device button.
`[Return]` | In examples, a key name enclosed in a box indicates that you press a key on the keyboard. (In text, a key name is not enclosed in a box.) In the HTML version of this document, this convention appears as brackets, rather than a box.
... | A horizontal ellipsis in examples indicates one of the following possibilities: Additional optional arguments in a statement have been omitted. The preceding item or items can be repeated one or more times. Additional parameters, values, or other information can be entered.
. . . | A vertical ellipsis indicates the omission of items from a code example or command format; the items are omitted because they are not important to the topic being discussed.
( ) | In command format descriptions, parentheses indicate that you must enclose choices in parentheses if you specify more than one.
[ ] | In command format descriptions, brackets indicate optional choices. You can choose one or more items or no items. Do not type the brackets on the command line. However, you must include the brackets in the syntax for OpenVMS directory specifications and for a substring specification in an assignment statement.
| | In command format descriptions, vertical bars separate choices within brackets or braces. Within brackets, the choices are optional; within braces, at least one choice is required. Do not type the vertical bars on the command line.
{ } | In command format descriptions, braces indicate required choices; you must choose at least one of the items listed. Do not type the braces on the command line.
bold text | This typeface represents the introduction of a new term. It also represents the name of an argument, an attribute, or a reason.
italic text | Italic text indicates important information, complete titles of manuals, or variables. Variables include information that varies in system output (Internal error number), in command lines (/PRODUCER= name), and in command parameters in text (where dd represents the predefined code for the device type).
UPPERCASE TEXT | Uppercase text indicates a command, the name of a routine, the name of a file, or the abbreviation for a system privilege.
`Monospace text` | Monospace type indicates code examples and interactive screen displays. This typeface indicates UNIX system output or user input, commands, options, files, directories, utilities, hosts, and users. In the C programming language, this typeface identifies the following elements: keywords, the names of independently compiled external functions and files, syntax summaries, and references to variables or identifiers introduced in an example.
- | A hyphen at the end of a command format description, command line, or code line indicates that the command or statement continues on the following line.
numbers | All numbers in text are assumed to be decimal unless otherwise noted. Nondecimal radixes---binary, octal, or hexadecimal---are explicitly indicated.

# Chapter 1
What Is IPv6?

In the early 1990s, members of the Internet community realized that the address space and certain aspects of the current TCP/IP architecture were not capable of sustaining the explosive growth of the Internet. The problems included the exhaustion of the Internet address space, the size of routing tables, and requirements for new technology features.

The Internet Engineering Task Force (IETF) made several efforts to study and improve the use of the 32-bit Internet Protocol (IPv4) addresses. They also tackled the longer-term goal of identifying and replacing protocols and services that would limit growth.

These efforts identified the 32-bit addressing architecture of IPv4 as the principal problem affecting router overhead and network administration. In addition, IPv4 addresses were often unevenly allocated in blocks that were too large or too small; therefore, these addresses were difficult to change within any existing network.

In July 1994, the Internet Protocol Next Generation (IPng) directorate announced Internet Protocol Version 6 (IPv6) as the replacement network layer protocol, and IETF working groups began to build specifications. (See RFC 1752, The Recommendation for the IP Next Generation Protocol, for additional information about the IPv6 protocol selection process.)

IPv6 is both a completely new network layer protocol and a major revision of the Internet architecture. As such, it builds upon and incorporates experience gained with IPv4. This chapter describes the following:

- Terminology
- IPv6 addressing
- IPv6 environment
- IPv6 configuration
- Postconfiguration tasks

# 1.1 Terminology

The following terms are used in this chapter:

- Node
  Any system that uses the IPv6 protocol to communicate.
- Router
  A node that forwards IPv6 packets addressed to other nodes. These systems typically have more than one network interface installed and configured.

- Host
  Any system that is not a router.
- Link
  A medium or facility over which nodes communicate with each other at the Link layer. Examples include Ethernet, FDDI links, or internet layer tunnels.
- interface
  A node's attachment to a link. An interface is usually assigned an IPv6 address or addresses.

# 1.2 Introduction to IPv6 Addresses

The most noticeable feature of IPv6 is the address itself. The address size is increased from 32 bits to 128 bits. The following sections describe the components of the IPV6 address.

## 1.2.1 Address Text Representation

Use the following syntax to represent IPv6 addresses as text strings:

    x:x:x:x:x:x:x:x

The x is a hexadecimal value of a 16-bit piece of the address. For example, the following addresses are IPv6 addresses:

    FEDC:BA98:7654:3210:FEDC:BA98:7654:3210

    1070:0:0:0:0:800:200C:417B

IPv6 addresses can contain long strings of zero (0) bits. To make it easier to write these addresses, you can use a double colon (::) once in an address to represent one or more 16-bit groups of zeros. For example, you can compress the second IPv6 address example in the following way:

    1070::800:200C:417B

Alternately, you can use the following syntax to represent IPv6 addresses in an environment of both IPv4 and IPv6 nodes:

    x:x:x:x:x:x:d.d.d.d

In this case, x is a hexadecimal value of a 16-bit piece of the address (six high-order pieces) and d is a decimal value of an 8-bit piece of address (four low-order pieces) in standard, dotted-quad IPv4 form. For example, the following are IPv6 addresses:

    0:0:0:0:0:0:13.1.68.3

    0:0:0:0:0:FFFF:129.144.52.38

When compressed, these addresses are as follows:

    ::13.1.68.3

    ::FFFF:129.144.52.38

Like IPv4 address prefixes, IPv6 address prefixes are represented using the Classless Inter-Domain Routing (CIDR) notation. This notation has the following format:

    ipv6-address/prefix-length

For example, you can represent the 60-bit hexadecimal prefix 12AB00000000CD3 in any of the following ways:

    12AB:0000:0000:CD30:0000:0000:0000:0000/60

    12AB::CD30:0:0:0:0/60

    12AB:0:0:CD30::/60

## 1.2.2 Types of Addresses

There are three types of IPv6 addresses:

- Unicast
- Anycast
- Multicast

  Note Unlike IPv4, IPv6 does not define a broadcast address. To get the function of a broadcast address, use a multicast address. (See Section 1.2.2.3.)

The following sections describe the unicast, anycast, and multicast address types.

### 1.2.2.1 Unicast Addresses

A unicast address is an identifier for an interface. Packets sent to a unicast address are delivered to the node containing the interface that is identified by the address.

Figure 1-1 shows the format of unicast addresses.

Figure 1-1 Unicast Addresses

This address typically consists of a 64-bit prefix followed by a 64-bit interface ID, as shown in Figure 1-2.

Figure 1-2 64-Bit Prefix Plus 64-Bit Interface ID

An interface ID identifies an interface on a link. The interface ID is required to be unique on a link, but it may also be unique over a broader scope. In many cases, the interface ID is derived from its Link layer address. The same interface ID can be used on multiple interfaces on a single node.

The following list describes commonly used unicast addresses and their values:

- Unspecified address
  Indicates the absence of an address and is never assigned to an interface. The unspecified address has the following value:

      0:0:0:0:0:0:0:0 (normal form)

      :: (compressed form)

- Loopback address
  Used by a node to send IP datagrams to itself and is typically assigned to the loopback interface.
  The IPv6 loopback address has the following value:

      0:0:0:0:0:0:0:1 (normal form)

      ::1 (compressed form)

- IPv6 addresses with embedded IPv4 addresses
  Used in mixed IPv4 and IPv6 environments and can be either of the following:
  - IPv4-compatible IPv6 address
    Used by IPv6 nodes to tunnel IPv6 packets across an IPv4 routing infrastructure. The IPv4 address is carried in the low-order 32 bits. Figure 1-3 shows the format of the IPV4-compatible IPV6 address.

    Figure 1-3 IPv4-Compatible IPv6 Address

    Note Do not use IPv4-compatible IPv6 addresses in DNS or in TCPIP$ETC:IPNODES.

  - IPv4-mapped IPv6 address
    Used to represent an IPv4 address and to identify nodes that do not support IPv6. This address is not used in an IPv6 packet. Figure 1-4 shows the format of the IPv4-mapped IPv6 address.

    Figure 1-4 IPv4-Mapped IPv6 Address

- Local-use IPv6 unicast addresses can be either of the following:
  - Link-local
    Used for addressing on a single link when performing address autoconfiguration or neighbor discovery or when no routers are present. Figure 1-5 shows the format of the link-local address.

    Figure 1-5 IPv6 Link-Local Unicast Address

  - Site-local
    Used for sites or organizations that are not connected to the global Internet. Figure 1-6 shows the format of the site-local address.

    Figure 1-6 IPv6 Site-Local Unicast Address

    If you plan to use site-local addresses, be aware of the following guidelines:
    - Do not connect a single node to multiple sites.
    - Do not use site-local addresses in the global DNS (the addresses should not be visible outside the site).
    - Do not advertise or propagate routes containing site-local prefixes outside the site.

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