Lesson 4 - Chapter 3: Network Addressing With IPv6 Flashcards
How many bits are IPv6 addresses?
128-bits (compared to 32-bits for IPv4)
Where IPv4 addresses are converted to decimal for humans to remember better, IPv6 is converted to what?
Hexadecimal
An IPv4 address has 4 segments. How many does an IPv6 have?
8
What’s the difference in how the decimal/hexadecimal numbers are separated in IPv4 and IPv6 addresses?
IPv4 = dots (periods)
IPv6 = colons
Are IPv6 addresses case-sensitive?
No
To shorten an IPv6 address, what do you do with the 0’s?
Leading zeros = omitted from a group(replaced with ::) or shrunk down to one 0
Examples
00CF = CF
0000 = 0
To shorten an IPv6 address, what can you do with all-zero groups 0000?
You can omit them and indicate them by placing 2 colons in their place
Example
2001:0000:0000:3210:0800:200C:00CF:1234
0000:0000:0000:0000:0000:0000:0000:0001/128
Becomes
2001::3210:800:200C:CF:1234
0:0:0:0:0:0:0:1 or ::1/128
What bits of an IPv6 address are for the host ID?
the last 64 bits
What is the Extended Unique Identifer-64-bit? (EUI-64)
the host ID that Linux and macOS build from the MAC address of the NIC
How does Windows generate the host ID of an IPv6 address? Does it ever change?
it generates a random value when a NIC is configured
(that number never changes)
What’s the abbreviated loopback address for IPv6?
0:0:0:0:0:0:0:1 or ::1/128
(entirely a host address, no network address)
Since IPv6 doesn’t have a subnet mask, what does it use that’s similar?
a prefix length
What’s a prefix length? What does it control?
controls how many address bits define the network (and the rest define the host address)
What’s the default prefix length?
64 bits written as /64
(so IPv6 128 bits is divided equally)
Name the 4 parts of an IPv6 address
- Global prefix
- Network prefix
- Subnet ID
- Interface ID
Describe the 4 parts of an IPv6 address
- Global prefix (first 4 digits)
- Network prefix (first 16 digits + global prefix)
- Subnet ID (last 2 digits of Network prefix)
- Interface ID (17th-32nd digits)
With IPv6, a single network card will have multiple….?
IP addresses
What’s a link-local address?
the IPv6 address a computer gives itself when it first boots up (will always have this address, does not indicate a connection issue)
(similar to IPv4’s APIPA local address)
The first 64 bits of a link-local IPv6 address are?
fe80::/10
(fe80:0000:0000:0000)
The remaining 64 bits of an IPv6 address is the?
Interface ID (equivalent to IPv4 Host ID)
Link-local addressing does all the local networking hard work so that you don’t need to mess with what 2 things?
static and DHCP addressing unless you have dedicated servers
To use the Internet with IPv6, what does a system need?
a 2nd IPv6 address called a global unicast address (also called global address)
What is a global unicast address also called?
global address (and it’s the 2nd IPv6 address needed to access the Internet)
How do you get a global address?
Most common is to request it from the default gateway router (as long as it’s configured to give out global IPv6 addresses)
What is a router solicitation (RS) message? What does it look for?
it’s a special packet sent out by a computer that was just plugged into a network to look for a router
What does a router do with a router solicitation (RS) message?
it responds with a router advertisement (RA)
What does a router advertisement (RA) do?
tells the computer that sent the RS its new network ID and subnet (together called the prefix) and DNS server if configured
What defines the “prefix” that a router sends out in a router advertisement (RA)?
it tells systems their network ID and subnet
What address does a router solicitation (RS) message use?
FF02::2
What computers read the address used for RS messages?
the only computers that read that address are computers running IPv6 in the network
The address that an RS message uses is called a..?
multicast address (not similar to a broadcast address, there’s no broadcast in IPv6)
What happens when a computer’s RS message is answered by the router and it gets its prefix?
it generates the rest of the address and ends up with a 128-bit public IPv6 address and a link-local address
Is this process the same in all 3 OS?
Yes
How is using a global address different from IPv4 addresses?
A global address sends you straight to the Internet, doesn’t rely on the router translating from local address to a network one
What’s a word of caution to keep in mind with computers that are running IPv6 and also have global addresses?
they can access your system unless you have a firewall (because data no longer needs to be routed through the router)
Instead of using a ___ ___ IPv6 addresses use a ___ ___ to indicate the divider between the network ID and host ID
instead of using a subnet mask, IPv6 addresses use a prefix length
Each host using IPv6 has a ___ ___ ___ that it generates itself
link-local address
To get on the Internet, each host uses what from the default gateway router?
the host uses a global unicast address from the default gateway router
What’s the range of hexadecimal numbers?
0-9
A-F