IPv6

Content  History  IPv4 Downfall  IPv6 Features  IPv6 Addresses  Changes from IPv4  IPv6 Headers/Frames/Packets  Autoconfiguration  Commands  Resources

What should I learn from this?  Know what a IPv6 Address looks like  Have an idea why IPv6 is need and should be important to me  How to troubleshoot low level issues  How to look at an IPv6 header and have an idea what is going on with it  Know where to go to ask questions about IPv6  Know what ISATAP, Dual Stack and 6RD are

History of IP IPv4IPv6 Dates1969 DARPA started research, 1981 IPv4 RFC Data32 Bits128 Bits NotationDecimalHexadecimal Size2^32 addresses (4,294,967,296) 2^128 addresses (340,282,366,920,938, 463,463,374,607,431, 768,211,456) Example /242001:558:4020::1/56 User SubnetDoes not exist/64, or (2^32)^2 – each household gets the size of IPv4 public addresses squared

IPv4 Downfall  IPv4 Addresses are almost gone  All IPv4’s have been assigned!  Everything using a single IP  Growing ISP’s require more IP Addresses  NAT issues

IPv6 Main Features  Larger address space for users and ISP to use with public access  Global capability  Plug – and – play  Multihoming Multihoming  Autoconfiguration  Renumbering (easy if setup right)  Simpler header – Streamlining of routing code  Address space

Types of IPv6 Addresses Global Unicast2000::/3 Link-Local UnicastFE80::/1 Loopback::1/128 6to42002::/16 Teredo2001:0000::/32 Unique Local UnicastFC00::/7 MulticastFF00::/8 IPv4 Mapped::ffff: Link-Local Multicast All- Nodes FF02::1 Private Address RangeFC00::/7 Non Routeable2001:0DB8::/32

Global Address  In IPv6 every host is publicly routable.  Each host has 2 IP addresses  Global address is your publicly routable address

Link Local Address  A link local address is like an IPv4 NATted address. When you connect your computer to a router, you get (DHCP) an IP Address like This same concept exists in IPv6, but is built into the protocol, and the start of the IP address will be ‘FE80:’  This IPv6 address is how your computer talks to the other computers that are on your same network.

Change From IPv4  Address length quadrupled to 16 bytes  Header Format Simplification  Fixed length, optional headers are daisy-chained  IPv6 header is twice as long (40 bytes) as IPv4 header without options (20 bytes)  No checksumming at the IP network layer  No hop-by-hop segmentation  Path MTU discovery  64 bits aligned  No more broadcast  No more fragmentation and reassembly in header  Incorrectly sized packets are dropped and message is sent to sender to reduce packet size  Hosts should do path MTU discovery

IPv6 Headers

IPv6 Header Extensions  Everything in IPv6 is a header extension – even TCP/UDP payload

IPv6 Full Example

Autoconfiguration  Built into the IPv6 protocol, there is the concept of IP autoconfiguration.  Stateless  In IPv4, you connect to the router, and your machine asks the DHCP server what IP address it should use.  In IPv6 the DHCP option is still there, but with autoconfiguration, your host negotiates its IP address with all of the other hosts that are on the network.

IPv6 Commands  ping6  nmap -6  traceroute -6  ssh -6  Web pages:  address]%[device]   Nslookup (AAAA record)

Resources   RFC  RFC  RFC  RFC  RFC  RFC           