IT2400 Chapter13
What is a valid IPv6 subnet mask?
/64
Link-local address always use
/64 as the subnet mask
How many bits comprise an IPv6 address?
128
IPv6 supports
2 ^128 (or 3.4 x 10^38) addresses
there are 4 popular tunneling standards
6to4, 6in4, Teredo and ISATAP
Ipv6 replaced broadcasts with multicasts
A multicast is a set of reserved addresses designed to go to only certain systems. Packets sent to addresses beginning with FF02::2 are only sent to routers
As IPv6 clients can get a portion of their IP address from the default gateway server, what purpose does a DHCPv6 server serve?
A) DHCPv6 servers can still distribute DNS server information.
Which of the following IPv6 addresses are equivalent to ACCB:0876:0000:0000:FD87:0000:0000:0064?
ACCB:876::FD87:0:0:64 ACCB:876:0:0:FD87::64
Which of the following is a valid link-local address?
B) FE80::1994:33DD:22CE:769B
Which operating systems fully support IPv6? (Select three.)
B) Windows XP C) Windows Vista D) Macintosh OS X
How do IPv6 multicasts differ from broadcasts?
Both broadcasts and multicasts are sent to all network nodes, but in a multicast, only the destination nodes read the incoming packets.
Which of the following is a valid IPv6 address?
C) 2541:FDC::ACDF:2770:23
What must your computer have to access the IPv6 Internet?
D) A global unicast address
DHCPipv6 servers may be bypassed by manually entering
DNS server information into the IP settings of an ipv6 clinet.
A packet has been sent to the address FF02:0000:0000:0002:0BCD:23DD:3456:0001. What will read the sent packet?
Every router on the network.
A link local address always starts with
FE80::. The last 64 bits of the link-local address are generated from the NIC's Mac address
in addition to IPv6 expanded address space
Ipv6 improves security by supporting IPSec out of the box
What is the main benefit of IPv6 aggregation?
It reduces the size and complexity of routing tables, allowing routers to work more efficiently.
What is true of link-local addresses?
The last 64 bits are always generated from the MAC address, except on Windows Vista and Windows 7.
What is true of current global addresses?
They always begin with 2001::, 2002::, 2003::, and so on.
Microsoft Windows Vista and Windows 7 generate the last 64 bits of a link-local address randomly so as to not reveal the Mac address
This adds security against hackers
IPv4 supports only
about 4 billion addresses which is no longer enough for the future
ISATAP
adds an ipv4 address to an ipv6 prefix. for example, 2001:DB8:98CA:200:131.107.28.9
ipv6 is active by default on Mac OSX
and active by default on most Linux installs using at least kearn2.6
Multicasts, like broadcasts,
are still sent to every computer on the network. Unlike broadcasts, through only the destined systems read the multicast packet
TSP and TIC
are two automatic configuration protocols for setting up IPV4-to-IPV6 tunnels
IPv6 address are composed of 128
bits written in hexadecimal notation. Every 4 bits are separated by a colon. 2001:0000:0000:3210:0800:200C:00CF:1234 is a valid Ipv6 address
Global unicast addresses are distributed
by the default gateway router, provided the router is configured to pass out global Ipv6 addresses
an ipv4-to-ipv6 tunnel
can be used to bridge the gap created by non ipv6 routers, allowing you access to the root and tier-one routers that do support ipv6
only 6in4 are teredo
can go through NAT
The first half of the global unicast address is called the prifix and
consits of the nework ID and subnet mask. The prefix is passed out by the default gateway router. The last half of the global address is self generated by the computer
Do not connect t the ipv6 internet on a
critical computer. limited ipv6 support means potential security risks
Stateful DHCPv6 servers pass out Ipv6 addresses, subnet masks,
default gateway addresses and DNS server addresses as well as other optional information
ipv6 doesn't support NAt.
every ipv6 address is exposed to the internet, use a good firewall.
Currently, all root DNS servers support IPv6 resolution and almost all tire-one ISP routers, properly
forward ipv6 pakcets. However the routers between you and these root and tier-one servers may not support Ipv6 at the moment
Computers using IPv6 that are on the internet
have two IPv6 addresses: a link-local address and a global address.
An Ipv6 computer not on the Internet needs only the self-generated link-local address to participate on a local network.
however, a server n such a network still needs a static IP address, not a random self-generated link-local address.
Stateless DHCPv6 servers pass out only optional
information. Stateless DHCPipv6 servers are preferred to stateful servers because stateless servers support aggregation.
An Ipv6 global unicast address is required for
internet access
Teredo is built
into the windows. Teredo addresses always start with 2001:0000:/32
link local address
is similar to an IPv4 APIPA address in that it is self-generated. the link-local address is guaranteed to be unique because it is partially based on the MAC address of the NIC
6to4
is the dominant tunneling protocol and is the only one that doens't require a tunnel brocker. however, it is the most challenging to set up. 6to4 addresses start with 2002:/16
What is the only type of IPv6 address required to communicate with other computers on a local network?
link-local
Leading zeroes can be dropped and double colons
may be used to represent consecutive groups of zeros in order to write an IPv6 address with fewer characters. 2001::3210:800:200C:CF:1234 is a valid IPv6 address.
IPv6 subnet masks are represented with a /X CIDR
naming convention. FEDC::CF:0:BA98:1234/64 translates to 64-bit subnet mask.
Ipv6 link-local address are unicast
or unique to a specific computer or network node.
Aggregation
reduces the size and complexity of routing tables by allowing downstream routers to use a subset of an upstream router's routes to populate its routing table rather than tens of thousands of disjointed routes
While Ipv6 global addresses are passed out by the default gateway
router (with a portion self generated) DHCP servers are still important because they pass out DNS Server information
IPv6 provides a more efficient
routing scheme because it uses aggregation
it is estimate that ipv4 addresses will run out
somewhere between the year 2011-2019
A tunnel broker is a service provider
that creates the tunnel, acts as the far endpoint, and often provides a tunneling client for easier setup
What type of address applies to a single unique network node?
unicast
Not all versions of windows support ipv6 and some that do enable it by default
whereas others require manual installation
