Dynamic Configuration of Ipv4 Link-Local Addresses

By Cheshire, S.

Book Id: WPLBN0000694299
Format Type: PDF eBook:
File Size: 0.1 MB
Reproduction Date: 2005

Title:	Dynamic Configuration of Ipv4 Link-Local Addresses
Author:	Cheshire, S.
Volume:
Language:	English
Subject:	Technology, Science, Tools.
Collections:	Technical eBooks and Manuals Collection, Technical eBooks Collection
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Citation APA MLA Chicago Cheshire, B. S. (n.d.). Dynamic Configuration of Ipv4 Link-Local Addresses. Retrieved from http://gutenberg.cc/

Description
Technical Reference Publication

Excerpt
Introduction: As the Internet Protocol continues to grow in popularity, it becomes increasingly valuable to be able to use familiar IP tools such as FTP not only for global communication, but for local communication as well. For example, two people with laptop computers supporting IEEE 802.11 Wireless LANs [802.11] may meet and wish to exchange files. It is desirable for these people to be able to use IP application software without the inconvenience of having to manually configure static IP addresses or set up a DHCP server [RFC2131]. This document describes a method by which a host may automatically configure an interface with an IPv4 address in the 169.254/16 prefix that is valid for Link-Local communication on that interface. This is especially valuable in environments where no other configuration mechanism is available. The IPv4 prefix 169.254/16 is registered with the IANA for this purpose. Allocation of IPv6 Link-Local addresses is described in IPv6 Stateless Address Autoconfiguration [RFC2462].

Table of Contents
Table of Contents 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements. . . . . . . . . . . . . . . . . . . . . . 3 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . 3 1.3. Applicability . . . . . . . . . . . . . . . . . . . . . 5 1.4. Application Layer Protocol Considerations . . . . . . . 6 1.5. Autoconfiguration Issues. . . . . . . . . . . . . . . . 7 1.6. Alternate Use Prohibition . . . . . . . . . . . . . . . 7 1.7. Multiple Interfaces . . . . . . . . . . . . . . . . . . 8 1.8. Communication with Routable Addresses . . . . . . . . . 8 1.9. When to configure an IPv4 Link-Local Address. . . . . . 8 2. Address Selection, Defense and Delivery . . . . . . . . . . . 9 2.1. Link-Local Address Selection. . . . . . . . . . . . . . 10 2.2. Claiming a Link-Local Address . . . . . . . . . . . . . 11 2.3. Shorter Timeouts. . . . . . . . . . . . . . . . . . . . 13 2.4. Announcing an Address . . . . . . . . . . . . . . . . . 13 2.5. Conflict Detection and Defense. . . . . . . . . . . . . 13 2.6. Address Usage and Forwarding Rules. . . . . . . . . . . 14 2.7. Link-Local Packets Are Not Forwarded. . . . . . . . . . 16 2.8. Link-Local Packets are Local. . . . . . . . . . . . . . 16 2.9. Higher-Layer Protocol Considerations. . . . . . . . . . 17 2.10. Privacy Concerns. . . . . . . . . . . . . . . . . . . . 17 2.11. Interaction between DHCPv4 and IPv4 Link-Local State Machines. . . . . . . . . . . . . . . . . . . . . 17 3. Considerations for Multiple Interfaces. . . . . . . . . . . . 18 3.1. Scoped Addresses. . . . . . . . . . . . . . . . . . . . 18 3.2. Address Ambiguity . . . . . . . . . . . . . . . . . . . 19 3.3. Interaction with Hosts with Routable Addresses. . . . . 20 3.4. Unintentional Autoimmune Response . . . . . . . . . . . 21 4. Healing of Network Partitions . . . . . . . . . . . . . . . . 22 5. Security Considerations . . . . . . . . . . . . . . . . . . . 23 6. Application Programming Considerations. . . . . . . . . . . . 24 6.1. Address Changes, Failure and Recovery . . . . . . . . . 24 6.2. Limited Forwarding of Locators. . . . . . . . . . . . . 24 6.3. Address Ambiguity . . . . . . . . . . . . . . . . . . . 25 7. Router Considerations . . . . . . . . . . . . . . . . . . . . 25 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 9. Constants . . . . . . . . . . . . . . . . . . . . . . . . . . 26 10. References. . . . . . . . . . . . . . . . . . . . . . . . . . 26 10.1. Normative References. . . . . . . . . . . . . . . . . . 26 10.2. Informative References. . . . . . . . . . . . . . . . . 26 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 27 Appendix A - Prior Implementations. . . . . . . . . . . . . . . . 28 3