7. IPv6 Addressing Flashcards
Why there is the need for IPv6? ( 2 )
- IPv4 is running out of addresses
- IPv4 has limited address space
- Ipv6 included fixes for IPV4 limitations and other enhancements
Will IPV4 and IPv6 conexist in the near future?
- Yes
- The transition will take several years
Who created various protocols and tools to help network administratiors migrate their network to IPv6?
- IETF
List out the migration techniques that was used by IETE to migrate to IPv6
- Dual Stack
- Runs both IPv4 and IPv6 - Tunneling
- Transporting IPv6 Packet over an IPv4 Network
- IPv4 packet is encapsulated inside an IPv4 packet - Translation
- NAT 64 allows IPv6 enabled devices to communicated with IPv4 enabled devices using translation technique similar to NAT for IPV4
What are the length of IPv6 and it was written in what?
- 128 bits
- Hexadecimal
Is IPv6 addresses case-sensitive?
- No ( can be written in either lowercase or uppercase )
What is the format for IPv6?
- X:X:X:X:X:X:X:X
- Each consisting four hexadecimal values
- It is called hextet
- It is 16 bits or 4 hexadecimal values
- 2001:0db8:0000:00a3:abcd:0000:0000:1234
- IPv4 is 32 bits
What does the rules that IETF created in IPv6 Representation ? ( 2 )
- Omit Leading Zero
- Omit the 0 if the value infront is 0 ( 01ab = 1ab ,0000 = 0 )
- Double Colon
- Double colon ( :: ) replace any single, contiguous string of one or more 16-bit hextets consisting all 0
2001: 0db8 : 0000 : 1111: 0000 : 0000 : 0000 : 0002
Rule 1
2001 : db8 : 0 : 1111 : 0 : 0 : 0 : 2
Rule 2
2001 : db8 : 0 : 1111 :: 2
List out the 3 broad categoeries of Ipv6 addresses
- Unicast
- Uniquely identifies an interface on an IPv6 enabled device
- Multicast
- Used to send a single IPv6 packet to multiple destinations
- Anycast
- Any IPv6 unicast address that can be assigned to multiple devices
- A packet sent to an anycast address is routed to the nearest device having that address
- IPv6 does not have a broadcast address
How does prefix length is represented in ?
- Slash notation
- Used to indicate the network portion of an IPv6 address
What are the length of IPv6?
- Range from 0 - 128
- Recommend length for LAN and most other types of network is /64
- Strongly recommended to use a 64 bit interface ID for most networks
List out the 2 types of unicast addresses
- Global Unicast Address ( GUA )
- Link-local Address ( LLA )
- IPv4 only have single addresses
What are the characteristics of IPv6 GUA ?
- Globally unique
- Routable on the IPv6 internet
What does Link-Local Address ( LLA ) required and what does it do?
- Required for every IPv6 enabled devices
- USed to communicate with other devices on the same local link
- It is not routable and are confined to a single link
What are the first 3 bits a being assigned to GUA?
- 0010
- 2000::/3
- Available GUA begins with a decimal 2 or 3 ( Only 1 / 8 th of the total available IPv6 address space )
List out the IPv6 GUA structure
- Global Routing Prefix
- Subnet ID
- Interface ID
Which IPv6 GUA structure is assigned by the ISP?
- Global Routing Prefix 9 48 bits )
- Vary depending on ISP policies
What IPv6 GUA structure is the area between Global Routing Prefix and Interface ID ?
- Subnet ID ( 16 bits )
What IPv6 GUA structure is equivalent to the host portion of an IPv4 address
- Interface ID ( 64 bit )
- Strongly recommended that in most cases /64 subnets should be used, which creates a 64-bit interface id
What does LLA devices enables devices to do?
- Enables a device to communicate with other IPv6 enabled devices on the same link and only on that link ( subnet )
What is the characteristics of IPv6?
- Packets with a source or destination LLA cannot be routed
- Every IPv6 enabled network interface must have an LLA
- If an LLA is not configured manually on an interface, the device will automatically create one.
What are the range of IPv6 LLA?
- fe80:: /10 range
What are the command for configuring IPv6? ( 4 )
- interface gigabitethernet 0/0/0
- ipv6 address 2001:db8:acad:1::1/64
- no shutdown
- exit
- Similar to IPv4 counterparts
Which of the router interface can be used as the default gateway?
- GUA or LLA
- Best practice is to use the LLA
- Manually configuring the IPv6 address on a host is similar to configuring an IPv4 address
What are used so the LLA of the router will automatically be specified as the default gatewat address? ( 2 )
- DHCPv6
- SLAAC
What is the command for configuring a LLA? ( 4 )
- interface gigabitethernet 0/0/0
- ipv6 address fe80::1:1 link-local
- no shutdown
- exit
- It lets us create an address that is recognizable and link-local command
Can we use the same LLA ?
- Yes , as long as it is unique on that link
- Best practice is to create a different LLA on each interface of the router to make it easy to identify the router and the specific interface
Where does devices obtain addresses dynamically through?
- Internet Control Message Protocol version 6 ( ICMPv6 )
What are the purpose of Router Solicitation ( RS ) ?
- Send messages by host devices to discover IPv6 routers
What are the purpose of Router Advertisement ( RA ) ?
- Sent by routers to inform host on how to obtain an IPv6 GUA and provide useful network information
List out the useful network information for provided by Router Advertisement?
- Network Prefix and Prefix Length
- Default Gateway Address
- DNS addresses and domain name
List out the 3 methods for configuring an IPv6 GUA
- SLAAC : IPv6 Stateless Address Auto-Configuration
- SLAAC with Stateless DHCPv6 server
- Stateful DHCPv6 ( no SLAAC )
SLAAC allows a device to configure a GUA without what? ( Method 1 )
- Services from DHCPv6
- Devices obtain the necessary information to configure a GUA from the ICMPv6 RA messages of the local router
- The prefix is provided by the RA and the device uses either the EUI-64 or random generation method to create an interface id
What can an RA instruct a device to use?
- SLAAC
- Stateless DHCPv6
What does the RA message use ? ( 3 )( Method 2 )
- SLAAC to create its own IPv6 GUA
- The router LLA, which is the RA source IPv6 address, as the default gateway address
- A stateless DHCPv6 server to obtain other information such as a DNS server address and a domain name
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What does SLAAC do?
- Allows a device to configure a GUA without the services of DHCPv6
What is the step of SLAAC ?
- Devices obtain the necessary information to configure a GUA from the ICMPv6 RA messages of the local router
- The prefix is provided by the RA and the device uses either the EUI-64 ( add ff : fe at the index 2 or 3 ipv6 address ) or random generation method to create an interface ID
- EUI-64 generate IPv6 based on MAC address
What can RA instruct? ( Method 2 )
- Instruct device to use both SLAAC and stateless DHCPv6
What does RA message suggest the device? ( 3 )
- SLAAC to create its own IPv6 GUA
- The router LLA, which is the RA source IPv6 address, as the default gateway address
- A stateless DHCPv6 server to obtain other information such as a DNS server address and a domain name
When must the client generate its own interface ID?
- When the RA message is either SLAAC or SLAAC with Stateless DHCPv6
How can the Interface ID be created?
- EUI-64 Process
- Randomly generated 64 bit number
What does EUI-64 adds to?
- A 16 bit value of fffe is inserted into the middle of the 48 bit Ethernet MAC address of the client
- The 7th bit of the client MAC address is reversed mfrom binary 0 to 1
- Example:
48-bit MAC - fc:99:47:75:ce:e0
EUI-64 - fe:99:47:ff:fe:75:ce:e0
Since what windows versions uses randomly generated interface ID instead of one created EUI-64?
- Windows Vista
- To ensure the uniqueness of any IPv6 unicast address, the client may use a process known as Duplicate Address Detection (DAD). This is similar to an ARP request for its own address. If there is no reply, then the address is unique
What does all IPv6 interfaces must have?
- IPv6 LLA
- LLA can be configured dynamically
What operating system will typically use the same method for both a SLAAC Created GUA and a dynamically assigned LLA
- Windows
List out the 2 types of IPv6
- Well-Known Multicase Addresses
- Solicited Node Multicast Addresses
- It have the prefix ff00::/8
What are well-known IPv6 multicast addresses assigned to?
- Predefined groups of devices