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

IPv4 IPv6

Dates 1969 DARPA started research, 1981 IPv4 RFC791

1999

Data 32 Bits 128 Bits

Notation Decimal Hexadecimal

Size 2^32 addresses (4,294,967,296)

2^128 addresses (340,282,366,920,938, 463,463,374,607,431, 768,211,456)

Example 192.168.1.0/24 2001:558:4020::1/56

User Subnet

Does 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 Autoconfiguration Renumbering (easy if setup right)

Simpler header – Streamlining of routing code

Address space

Types of IPv6 Addresses

Global Unicast 2000::/3

Link-Local Unicast FE80::/1

Loopback ::1/128

6to4 2002::/16

Teredo 2001:0000::/32

Unique Local Unicast FC00::/7

Multicast FF00::/8

IPv4 Mapped ::ffff:128.223.214.23

Link-Local Multicast All-Nodes

FF02::1

Private Address Range FC00::/7

Non Routeable 2001:0DB8::/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 192.168.1.101. 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: http://[IPv6 address]%[device] http://fe80::21c:42ff:fe00:9%eth1

Nslookup (AAAA record)

Resources

http://www.cisco.com/en/US/technologies/tk648/tk872/technologies_white_paper0900aecd8054d37d.html

RFC2460 http://www.ietf.org/rfc/rfc2460.txt RFC4861 http://www.ietf.org/rfc/rfc4861.txt RFC4862 http://www.ietf.org/rfc/rfc4862.txt RFC4942 http://www.ietf.org/rfc/rfc4942.txt RFC5157 http://www.ietf.org/rfc/rfc5157.txt RFC3756 http://www.ietf.org/rfc/rfc3756.txt http://www.iol.unh.edu/services/testing/ipv6/ http://nmap.org/book/man-host-discovery.html http://www.cs.columbia.edu/~smb/papers/v6worms.pdf http://www.uninformed.org/?v=10&a=3 http://www.infosecwriters.com/text_resources/pdf/IPv6_SSotillo.pdf http://freeworld.thc.org/thc-ipv6/ http://freeworld.thc.org/papers/vh_thc-ipv6_attack.pdf http://www.rmv6tf.org/RMv6TFDocs.htm http://defcon.org/images/defcon-18/dc-18-presentations/Bowne/DEFCON-18-Bown

e-IPv6.pdf http://defcon.org/images/defcon-18/dc-18-presentations/Curran/DEFCON-18-Curra

n-IPv6.pdf http://defcon.org/images/defcon-18/dc-18-presentations/Ryanczak/DEFCON-18-Ry

anczak-IPV6.pdf