<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML ><HEAD ><TITLE >Address types</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="Linux IPv6 HOWTO (en)" HREF="index.html"><LINK REL="PREVIOUS" TITLE="FAQ (Basics)" HREF="x446.html"><LINK REL="NEXT" TITLE="Addresses without a special prefix" HREF="x475.html"></HEAD ><BODY CLASS="CHAPTER" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >Linux IPv6 HOWTO (en)</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="x446.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="x475.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="CHAPTER-ADDRESSTYPES" ></A >Chapter 3. Address types</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT >3.1. <A HREF="x475.html" >Addresses without a special prefix</A ></DT ><DD ><DL ><DT >3.1.1. <A HREF="x475.html#AEN477" >Localhost address</A ></DT ><DT >3.1.2. <A HREF="x475.html#AEN484" >Unspecified address</A ></DT ><DT >3.1.3. <A HREF="x475.html#AEN492" >IPv6 address with embedded IPv4 address</A ></DT ></DL ></DD ><DT >3.2. <A HREF="x512.html" >Network part, also known as prefix</A ></DT ><DD ><DL ><DT >3.2.1. <A HREF="x512.html#AEN517" >Link local address type</A ></DT ><DT >3.2.2. <A HREF="x512.html#AEN534" >Site local address type</A ></DT ><DT >3.2.3. <A HREF="x512.html#AEN550" >Unique Local IPv6 Unicast Addresses</A ></DT ><DT >3.2.4. <A HREF="x512.html#AEN562" >Global address type "(Aggregatable) global unicast"</A ></DT ><DT >3.2.5. <A HREF="x512.html#AEN608" >Multicast addresses</A ></DT ><DT >3.2.6. <A HREF="x512.html#AEN648" >Anycast addresses</A ></DT ></DL ></DD ><DT >3.3. <A HREF="x658.html" >Address types (host part)</A ></DT ><DD ><DL ><DT >3.3.1. <A HREF="x658.html#AEN662" >Automatically computed (also known as stateless)</A ></DT ><DT >3.3.2. <A HREF="x658.html#AEN678" >Manually set</A ></DT ></DL ></DD ><DT >3.4. <A HREF="x683.html" >Prefix lengths for routing</A ></DT ><DD ><DL ><DT >3.4.1. <A HREF="x683.html#AEN689" >Prefix lengths (also known as "netmasks")</A ></DT ><DT >3.4.2. <A HREF="x683.html#AEN704" >Matching a route</A ></DT ></DL ></DD ></DL ></DIV ><P >Like IPv4, IPv6 addresses can be split into network and host parts using subnet masks.</P ><P >IPv4 has shown that sometimes it would be nice, if more than one IP address can be assigned to an interface, each for a different purpose (aliases, multi-cast). To remain extensible in the future, IPv6 is going further and allows more than one IPv6 address to be assigned to an interface. There is currently no limit defined by an RFC, only in the implementation of the IPv6 stack (to prevent DoS attacks).</P ><P >Using this large number of bits for addresses, IPv6 defines address types based on some leading bits, which are hopefully never going to be broken in the future (unlike IPv4 today and the history of class A, B, and C).</P ><P >Also the number of bits are separated into a network part (upper 64 bits) and a host part (lower 64 bits), to facilitate auto-configuration.</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="x446.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="x475.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >FAQ (Basics)</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Addresses without a special prefix</TD ></TR ></TABLE ></DIV ></BODY ></HTML >
