1.7 IPv4 Addressing Flashcards
N10-009 Obj. 1.7 Given a scenario, use appropriate IPv4 network addressing. (15 cards)
What is an IPv4 address and what format does it follow?
An IPv4 address uniquely identifies a device on a network and uses four decimal numbers (octets) separated by periods, e.g., 192.168.1.165.
Transcript: 0:12–0:32 “The IP address is a series of four numbers separated by a period. This would be something like 192.168.1.165.”
What is the purpose of a subnet mask in IPv4?
It determines which portion of the IP address refers to the network and which refers to the host.
Transcript: 0:41–1:11 “The subnet mask is used in conjunction with the IP address to determine what IP subnet this particular device is on… It’s instead used by your local device to make the determination of what devices are local on this IP subnet and what IP addresses may be outside of this local IP subnet.”
What is a default gateway in IPv4 networking?
A device’s local router IP used to forward traffic outside its local subnet.
Transcript: 1:12–1:49 “The default gateway is the IP address of a device that’s on your local subnet that allows you to communicate outside of this subnet… For example, if we have an IP address of 192.168.1.165 and a subnet mask of 255.255.255.0, a common default gateway could be 192.168.1.1.”
What is the IPv4 loopback address range and its primary use?
127.0.0.1 to 127.255.255.254; used to test local TCP/IP stack functionality.
Transcript: 2:00–2:31 “Every device on the network has a loopback address. And it’s a number that is between 127.0.0.1 through 127.255.255.254… This is often used to confirm that your local IP stack is working properly.”
What is the IPv4 reserved address range and what is it used for?
Class E addresses: 240.0.0.1 to 254.255.255.254; reserved for future use or testing.
Transcript: 2:39–3:04 “This is a range of IP addresses that should never be assigned to other devices… This range of reserved addresses is 240.0.0.1 through 254.255.255.254.”
What is a Virtual IP (VIP) address?
An IP address not tied to a physical interface, often used by virtual machines or internal router functions.
Transcript: 3:08–3:40 “It’s a virtual IP address, or a VIP. Virtual IP addresses are not associated with a physical Ethernet adapter… For example, you might assign a VIP to a virtual machine.”
At which OSI layer does IPv4 operate?
Layer 3 – the Network Layer.
Transcript: 3:45–3:48 “The IP protocol and IP version 4 operate at OSI layer three.”
How many bits are in an IPv4 address, and what is the max value per octet?
32 bits total (4 octets); max value per octet is 255.
Transcript: 4:22–4:46 “If you were to count up all of these bits, there are 32 total bits in an IP version 4 address. And that is the same as 4 bytes or 4 octets… the maximum value that you would ever have in decimal for any of these groups would be a maximum of 255.”
What protocol automatically assigns IPv4 addresses to devices on a network?
DHCP (Dynamic Host Configuration Protocol).
Transcript: 5:11–5:37 “Today, of course, we can plug in any of our devices. And it automatically receives an IP address. The way that we are able to receive this automated IP addressing is through a protocol known as DHCP, or Dynamic Host Configuration Protocol.”
What is APIPA and its address range?
Automatic Private IP Addressing; used when DHCP fails. Range: 169.254.0.1 to 169.254.255.254 (excluding first and last 256 addresses).
Transcript: 6:14–6:52 “In IP version 4, this link-local address is assigned through a process known as Automatic Private IP Addressing, or APIPA. This range of IP addresses automatically assigned through APIPA is 169.254.0.1 through 169.254.255.254… So if you receive an APIPA address on your device, it’s between 169.254.1.0 through 169.254.254.255.”
How does a device select an APIPA address?
It uses ARP to verify the address isn’t already in use on the local subnet.
Transcript: 7:00–7:11 “It uses ARP to confirm that no one else on your local network has that link-local address. And if nothing responds to that Address Resolution Protocol query, then it will assign a random number between that functional block.”
Why were private IP address ranges introduced in IPv4?
To overcome address exhaustion by using ranges that aren’t routed on the public internet.
Transcript: 7:17–7:56 “One of the challenges with IPv4 is that there are far more devices in the world than there are IP version 4 addresses… We refer to these as a private IP address range. And anything that is a private IP address cannot be routed on the public internet.”
What is Network Address Translation (NAT)?
A method that allows private IP addresses to communicate with the public internet by translating them to public IPs.
Transcript: 8:23–8:38 “We’re able to do that through a functionality called network address translation. This allows us to convert a private IP address into a public IP address and use that public IP address to communicate on the public network.”
What RFC defines private IPv4 address ranges?
RFC 1918.
Transcript: 8:40–8:50 “If you want to learn more about private IP addresses, you may want to reference a Request For Comment, or RFC. RFC 1918 is the standard that defines these ranges of private IP addresses and how they can be used on our networks.”
What are the three private IP address ranges defined by RFC 1918?
10.0.0.0/8 (16 million+ addresses)
172.16.0.0/12 (1 million+ addresses)
192.168.0.0/16 (65,000+ addresses)
Transcript: 9:01–10:40 “These three ranges are 10.0.0.0 through 10.255.255.255… 172.16.0.0 through 172.31.255.255… 192.168.0.0 through 192.168.255.255… The CIDR block notation for this would be 192.168.0.0/16. And that /16 subnet mask is the same as 255.255.0.0.”
