CNT 206 Module 12: Ipv6 Addressing

Method 2: SLAAC and Stateless DHCPv6

"Here is your prefix, prefix-length, and default gateway address. But you need to get the DNS information from a stateless DHCPv6 server" uses SLAAC (prefix & prefix length) and EUI-64 or randomly generated 64-bit number (interface ID) to make GUA uses router LLA (src IP of RA) to default-gateway address DHCPv6 stateless server for DNS server address and domain name

Method 3: Stateful DHCPv6

"I am your default gateway, but you need to ask a stateful DHCPv6 server for your IPv6 address and other info." Router messages suggest: Router LLA --> default gateway stateful DHCPv6 server --> GUA, DNS server address, domain name, and other info

Well-Known IPv6 Multicast Addresses

- ff00::/8 prefix - used for predefined groups of devices - used to reach group of devices running on common protocol or service ff02::1 - all-nodes multicast group: same effects as IPv4 broadcast all IPv6 enabled devices join ff02::1 - all-routers multicast group all IPv6 routers join

3 parts of EUI-64 interface ID

1. 24-bit OUI from the client MAC address, but the 7th bit (the Universally/Locally (U/L) bit) is reversed. This means that if the 7th bit is a 0, it becomes a 1, and vice versa. 2. The inserted 16-bit value fffe (in hexadecimal) in the middle. 3. 24-bit Device Identifier from the client MAC address.

What are four issues with IPv4 that IPv6 resolves?

1. Address depletion 2. Too complex of a network, not allowing end-to-end connectivity with use of NAT 3. no address resolution 4. no address autoconfiguration

3 parts of an Ipv6 address. What's included in the prefix?

1. global routing prefix (/48) 2. subnet ID (/16) 3. interface ID (/64) prefix included global routing prefix and subnet ID

What are the two strategies used to reduce number of digits needed to represent an IPv6 address?

1. omitting the leading 0's within each hextet 2. using a :: to represent 1 or more hextets entirely made up of 0s

stateless DHCPv6 server vs. stateful DHCPv6 server

A stateless DHCPv6 server distributes DNS server addresses and domain names. It does not allocate GUAs. A stateful DHCPv6 server allocates and maintains a list of which device receives which IPv6 address. DHCP for IPv4 is stateful.

How many RIRs have run out of IPv4 addresses?

All 5

True or false. By default all routers are added to the all-routers multicast group when configured with a GUA.

False; global configuration command: ipv6 unicast-routing

translation; what kind of router is required

NAT64 translates IPv6 packets into IPv4 and vice versa to allow IPv4 and IPv6 networks to communicate You need and NAT64 enabled router

Do hosts have to use the IPCMPv6 RA messages to configure their addressing information?

No; The ICMPv6 RA message is a suggestion to a device on how to obtain an IPv6 GUA. The ultimate decision is up to the device operating system.

True or False? There is no broadcast address for IPv6.

True

True or False? Routers will not forward packets that include a link-local address as either the source or destination address.

True; link-local addresses only have relevance within the local link

True or False? Operating systems, like Windows, typically use the same method for both the SLAAC-created GUA and a dynamically created LLA.

True; you'll see the same digits appear in corresponding locations within link-local and GUA If EUI-64 was used for the interface ID, you'll be able to recognize the halves of the MAC OUI used and fffe in the LLA and GUA If a randomly generated 64-bit number was used, the IPv6 address (GUA) and the LLA will have identical interface ID numbers (prefixes will be different though to match type of unicast)

When does a client have to generate their own interface ID?

When they used either the SLAAC method or the SLACC with stateless DHCPv6 server method

Are any addresses in Ipv6 reserved?

Yes; all-1's host addresses can be assigned to host devices because there is no broadcast address in IPv6. all-0's can be assigned as well, but it IS reserved as a subnet-router anycast address, so it must be assigned to a router

Dual-stack

a category of migration techniques that allows IPv4 and IPv6 to coexists, both stacks running simultaneously native IPv6 ~ customer network has IPv6 connection to their ISP and to internet access

show ipv6 route

a command to show the IPv6 routing table router = [up/up] when configured with GUA and added to table as connected (C) route

tunneling; what kind of router is required?

a migration technique category where IPv6 packets are tunneled through IPv4-only network by encapsulating it into an IPv4 packet If it has to travel from an IPv6-only network to another IPv6 network with and IPv4 network being used in between during its hops, that means it'll need a dual stack router that will allow for both IPv4 and IPv6 protocol stacks to run

show ipv6 interface brief

command that displays abbreviated output for each of the interfaces displays IPV6 address of each Ethernet interface

What kind of address is this? 2001:0db8:1:acad::fe55:6789:b210

global unicast

What kind of address is this? 2033:db8:1:1:22:a33d:259a:21fe

global unicast

How do you enable a router as as an IPv6 router

ipv6 unicast-routing command

what kind if address is this? fe80::3201:cc01:65b1

link-local

Difference between Unique-local address and link-local address

link-local address is only used within it's link and isn't routable, a unique-local address is routable within it's routable domain. a unique-lcoal address still isn't accessible from the internet using a unique local address alone is not proper security measures

What is the minimum configuration for a router interface that is enabled for IPv6?

link-local address; Topic 12.3.0 - With IPv6, a router interface typically has more than one IPv6 address. The router will at least have a link-local address that can be automatically generated, but the router commonly has an global unicast address also configured.

What kind of address is this? ::1

loopback address

What kind of address is this? ff00::db7:4322:a231:67c

mulitcast

What kind of address is this? ff00::

multicast

What kind of address is this? ff02::2

multicast; all-routers group

x:x:x:x:x:x:x:x - what does this represent? how many digits does each x represent? how many bits? how many bits total are shown?

preferred format of IPv6 addresses; 4 digits; 16 bits (each digit = 4 bits); 128 bits

solicited-node multicast address

similar to all-noded multicast w/ advantage of the address being mapped to a special Ethernet multicast address this allows the Ethernet NIC to look at layer 2 information and decided if its destined for it without having to send to the IPv6 process

Method 1: SLAAC

the first method that can be used to dynamically configure a host device "I have everything you need including the prefix, prefix length, and default gateway address (router's LLA/src of RA message." creates own GUA without services from a DHCPv6 server (host will have to generate theiw own interface ID though either randomly or with the EUI-64 method)

What are migration techniques? And what are the 3 different categories of migration techniques?

the method of transitioning to IPv6 addressing now that networks worldwide are in need of them 1. dual-stack 2. tunneling 3. translation

What are the 3 types of IPv6 address? Define their purpose.

unicast - it uniquely identifies an interface on and IPv6 enabled device multicast - used to send a single packet to multiple devices at once anycast - Ipv6 unicast can be assigned to multiple devices; packet sent to anycast is sent to closest once with that unicast address.

What kind of address is this? fc00:22:a:2::cd4:23e4:76fa

unique local

compressed format

using both strategies to reduce number of digits in an Ipv6 address

ping

verify layer 3 connectivity