IPv6 Flashcards
Length of IPv4 address
32 bit
Length of an IPv6 address
128 bit
IPv6 improvements
128 bit
IPsec
aggregation (smaller routing table)
doesn’t need DHCP
what does IPv6 use to communicate on a local network
- link-local addressing (unicast)
- (like IPv4 APIPA)
- every address starts with fe80::/10
fe80: 0000:0000:0000 - 2nd 64 bits are generated randomly, on older systems like XP and server 2003, uses the MAC address to create called Extended Unique Identifier, 64-bit (EUI-64)
Parts of IPv6
- 8 Groups called quartet or hextet (between 0000 and ffff) separated by colons
- first 64 bits are the network prefix (for routing)
- 48 bit Global routing prefix (from upstream router)
- 16 bit subnet ID
- 2nd 64 bits are user address, called interface ID
rules to shorten an IPv6 address
- leading zeroes can be dropped from each quartet (so 00cf becomes cf, 0000 becomes 0)
- use :: for groups of zeroes (only once)
multicast
- a set of reserved addresses designed to go only to certain systems
- every system see’s the frame, but only computers set up to process the frame process it
IPv6 multicast addresses
ff02: :1 - all nodes address
ff02: :2 - all routers address
ff02: :1:ffxx:xxxx - solicited node address
Root hints
file of the IP addresses of the root DNS servers of the internet
anycast
- gives a number of computers the same IP address
- routers use BGP to determine which computer in the cluster is closest
- sends packets only to closest computer
prefix delegation
tells the router to go upstream to the ISP and get a prefix to hand out
any changes upstream will pass downstream
what do computers on IPv6 need to access the internet
global unicast address
no-default routers
top tier routers, can’t have a default route
aggregation
every router underneath one router always uses a subset of that router’s existing routes
NDP
Neighbor Discovery Protocol
- has 5 packet types:
- neighbor solicitation - mulicast packet searching for other computers on its broadcast domain
- neighbor advertisement - response to solicitation
- router solicitation - request for a router advertisement (only happens when a computer hasn’t heard from the router recently)
- router advertisement - sends out addresssing information to all LAN hosts
- redirect
DHCPv6
- used if you dont want addressing from upstream
- stateful mode - passes out info like v4 DHCP
- stateless mode - uses router advertisements
4to6
IPv4-to-IPv6 tunnel
- encapsulate IPv4 traffic into an IPv6 tunnel, to get to an IPv6 capable router
6in4
IPv6-in-IPv4
- can go through IPv4 NAT
Teredo
Nat-traversal IPv6 tunneling protocol for windows
- start with 2001:0000:/32
- Miredo is open source for Unix/Linux
ISATAP
Intra-Site Automatic Tunnel Addressing Protocol
- works in an IPv4 network by adding the IPv4 address to an IPv6 prefix
Tunnel Brokers
create the actual tunnel and offer a custom-made enpoint client
- take advantage of one of two protocols:
TSP - Tunnel Setup Protocol
TIC - Tunnel Information and Control Protocol
Overlay Tunnels
enables two IPv6 networks to connect over existing IPv4 infrastructure
NAT64
transition mechanism that embeds IPv4 packets into IPv6
What kind of DNS records to IPv6 addresses use
AAAA
Is NAT needed with IPv6
No, the address space is so large that rationing routable addresses is unecessary
What is the /16 prefix for all 6to4 addresses?
2002
