Technology - IPv6 3 - Headers & DNS

Synopsis

In the context of Ethernet, IPv4, TCP and UDP headers, we describe the basic and extension headers which define the structure of IPv6 packets. We discuss the Hop-by-Hop, Destination Options, Routing, Fragmentation, Authentication, Encapsulation and Mobility extension headers. We also describe the IPv6 specific aspects of the Domain Name System, including reverse mapping of IPv6 addresses.

Table of Contents

• 1. Synopsis
• 2. Introduction
• 3. Headers
  • 3.1 Ethernet header
    • 3.1.1 Ethertype
  • 3.2 IPv4 header
  • 3.3 TCP header
  • 3.4 UDP header
  • 3.5 IPv6 header
    • 3.5.1 Extension headers
    • 3.5.2 Extension header lengths
    • 3.5.3 Order of Extension Headers
    • 3.5.4 Hop-by-Hop Options extension header
    • 3.5.5 Destination Options extension header
    • 3.5.6 Routing extension header
    • 3.5.7 Fragment extension header
    • 3.5.8 Authentication extension header (AH)
    • 3.5.9 Encapsulated Security Payload extension header (ESP)
    • 3.5.10 SHIM6 extension header
    • 3.5.11 Mobility extension header
• 4. Domain Name System (DNS)
  • 4.1 The AAAA record
  • 4.2 Reverse mapping
  • 4.3 A6 and DNAME abandoned
  • 4.4 Dynamic DNS
    • 4.4.1 Changing ISPs
• 5. Related reports

• Exhibit 1 – OSI layered model: a web-browsing, TCP/IP and Ethernet example