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Some thoughts and informations to IPv6

Disadvantages IPv4

  • NAT necessary difficult for connection of personal devices, back-channel
  • No true end-to-end connections are possible
  • Insufficient addresses
  • DHCP must be used mostly

IPv6 Addressing

  • 128 Bit Addess
  • Hex notation, 8 pairs of four-digit hexadecimal

2 Rules for IPv6 addresses

  • Eliminate Leading 0
  • Eliminate sequenced zeros and mark them with :: (only once)

IPv6 Types of Addresses


  • Starts with FE80
  • Rest is random
  • Like Apipa in IPv4 - but normal under IPv6
  • Built in conflict detection
  • Link-local adress are used for communication in the same subnet


  • Starts with FC00 or FD00
  • Like private IPv4-Address - but there is no need to use them any more


  • Starts with FF00

Global Scope

  • Starts with 2001, 2002
  • Routable, can be used on the internet
  • Global routing prefix 48 bits (or less) assigned to companys
  • Subnet ID starts after global routing prefix and is in the first 64 bits
  • Interface ID are the last 64 bits

Transitioining to IPv6

  • Dual-Stack Router: Devices that can handle IPv4 and IPv6
  • Dual IP layer architecture: The IS handles the both IP versions
  • IP tunneling: Tunnel IPv6 packets over IPv4 ore vice versa
  • ISATAP (Intra Site Autotmatic Tunnel Addressing Protocol)
    • Embedd IPv4 packet in IPv6
    • Isatap enabled router neccessary
    • Isatap A-Entry should be entered in DNS - per standard block
    • Ends with IPv4 adress and has :5EFE: is in the adress
  • Teredo
    • Tunnels IPv6 across IPv4 Internet
    • Needs special devices: Teredeo Server, Relay...

Special IPv6 addresses

  • /8 means that the first 8 Bytes are reserved for Network ID
  • ::1 Loopback-Adress
  • :: Gateway
  • %nn Index of connection
::1 Loopback-Adress %11 Index-ID per NIC