Net+ 4.2 - Lesson

IPv4 Facts

• IPv4 addresses are unique identifiers assigned to devices on a network.

• They are represented as a series of four decimal numbers separated by periods (e.g., 192.168.1.1).

• Behind the Scenes: Each decimal number actually represents a set of 8 bits (binary digits: 0s and 1s). We call these sets "octets".

Multiple Choice

How many bits in an IPv4?

• 32 bits
• 128 bits
• 64 bits
• 16 bits

Multiple Choice

IPv4 is known as WHAT notation?

• dotted-decimal notation
• octal notation
• hexadecimal notation
• binary notation

Multiple Choice

IPv4 can be read by humans because it is in WHAT numbering system?

• decimal
• octal
• hexadecimal
• binary

Fill in the Blank

Convert 11000011 into decimal

128/64/32/16/8/4/2/1

Fill in the Blank

Convert 01000010 into decimal

128/64/32/16/8/4/2/1

Fill in the Blank

Convert 00001111 into decimal

128/64/32/16/8/4/2/1

Fill in the Blank

Convert 0000001 into decimal

Fill in the Blank

Convert 1000001 into decimal

IPv4 Facts

• An IPv4 address functions like an address for a device on a network.

• It consists of two key parts:

  • Network ID (NetID): This identifies the specific network to which a device belongs, similar to an apartment building number. All devices on the same network share the same Network ID.

  • Host ID: This uniquely identifies a specific device within a network, just like an apartment number within a building identifies a particular residence.

Multiple Choice

This part of the IPv4 uniquely identifies a specific device within a network, just like an apartment number within a building identifies a particular residence

• Host portion of the IPv4 address
• Subnet mask
• Gateway address
• Network portion of the IPv4 address

Multiple Choice

This part of the IPv4 identifies the specific network to which a device belongs, similar to an apartment building number. All devices on the same network share the same _____.

• subnet mask
• gateway address
• network address
• host identifier

Net/Host ID

• Analogy:

  • Imagine a large apartment complex. The complex itself has a unique address (like a street address), which would be analogous to the Network ID in our IPv4 address.

  • Each individual apartment within the complex has its own unique number (like an apartment number), which is similar to the Host ID within an IPv4 address.

Net/Host ID

• Understanding the Relationship:

  • The Network ID portion of the address determines which network a device belongs to.

  • The Host ID portion differentiates between individual devices sharing that same network.

Match

Identify the parts of the IPv4, according to the subnet mask

• Subnet mask

• Net ID

• Host ID

255.255.255.0

192.100.1.x

x.x.x.20

• 255.255.255.0

• 192.100.1.x

• x.x.x.20

Match

Identify the parts of the IPv4, according to the subnet mask

• Subnet mask

• Net ID

• Host ID

255.255.0.0

192.100.x.x

x.x.1.20

• 255.255.0.0

• 192.100.x.x

• x.x.1.20

Subnets (external research)

• A subnet, or subnetwork, is a network inside a network. Subnets make networks more efficient. Through subnetting, network traffic can travel a shorter distance without passing through unnecessary routers to reach its destination.

  
  

Subnet Mask

• Subnet addressing has three hierarchical levels: a network ID, subnet ID, and host ID. 

• To further expand on the apartment analogy, you could refer to how the 1 in apartment 101 refers to the floor and the 01 refers to the unit number on that floor. Until you get to the correct floor, the last part of the number isn’t relevant. 

Subnet Mask

• To create logical subnets, bits from the host portion of the IP address must be allocated as a subnetwork address, rather than part of the host ID. 

• It is important to understand that only one mask is ever applied to the IP address on each interface. The mask containing the subnet information is only used within the IP network. External IP networks continue to address the whole network by its network ID.

Multiple Choice

Essentially subnet masks work internally or externally of a network?

• Only for routing
• Internally
• Only for security
• Externally

Multiple Choice

To find an external subnet mask of a host, your data must travel through THIS device.

• Switch
• Hub
• Modem
• Router

Multiple Choice

All subnet masks are the same on every network.

• All subnet masks are unique to each device.
• False
• True
• Subnet masks are only used in IPv6 networks.

Subnet Mask

• A subnet mask is 32 bits long (like the IP address)

• The number of 1s in the subnet mask identifies which bits in the IP address contain the network ID. 

Fill in the Blank

Determine the subnet mask based on the binary

11111111.11111111.00000000.00000000

.

.

.

Fill in the Blank

Determine the subnet mask based on the binary

11111111.11111111.11111110.00000000

.

.

.

Fill in the Blank

Determine the subnet mask based on the binary

11111111.11111111.11111111.00000000

.

.

.

Host Ranges

• Understanding IP address ranges can be likened to sorting mail in a large apartment building. 

  • Just as each apartment has a unique number to identify where mail should be delivered, every device on a network has a unique IP address. 

  • Think of the "network" part of an IP address as the building's address, and the "host" part as the specific apartment number. 

  
  

Host Ranges

• For instance, in a typical home network (like 192.168.1.x), the "192.168.1" can be seen as the building's address, while the "x" represents the specific apartment (or device) number. 

• Address ranges (like 192.168.1.1-192.168.1.254) tell us which "apartment numbers" are available for devices in this "building" — what addresses can be assigned to devices so they can communicate within the network.

Multiple Choice

If 192.168.1.1 has a subnet mask of 255.255.255.0, what is the network ID?

• 192.168.1.1
• 255.255.255.255
• 192.168.0.0
• 192.168.1.0

Multiple Choice

If the subnet mask of a network is 255.255.255.0, and the default gateway is 172.31.28.1, what is the NEXT available IP address?

• 172.31.28.255
• 172.31.28.3
• 172.31.28.2
• 172.31.28.0

Host Ranges - default gateway

• Continuing with our apartment building analogy… 

  • You can think of the default gateway as the main entrance or the lobby of the building. 

  • Just as you need to go through the lobby to reach the outside world, devices in your network use the default gateway to communicate with devices outside their local network — it's the path to the broader internet. 
    

Host Ranges - default gateway

• If the IP addresses are apartment numbers, and the network part is the building address, then the default gateway is essentially the address of the building's lobby, guiding the "mail" (or data packets) to and from the larger world of the internet efficiently.

Multiple Choice

The portion of an IP address scope that is responsible for letting internal traffic access external traffic is called

• subnet mask
• firewall
• router
• gateway

Multiple Choice

If a default gateway is not established, can you connect to youtube.com?

• No, you cannot connect to youtube.com without a default gateway.
• Yes, you can connect to youtube.com without a default gateway.
• You can connect to youtube.com using a VPN instead.
• A default gateway is only needed for local network access.

BROADCAST

• Keeping with our analogy…

  • Broadcast address allows a message to be sent to all devices on the network simultaneously.

  • The address is the last address in an IP network – where all the host bits are set to 1.

  • For the 192.168.1.x network, the broadcast address would be 192.168.1.255.

Multiple Choice

In an IP address scope of 192.168.1.1-192.168.1.255 with a subnet of 255.255.255.0, what would the broadcast address be?

• 192.168.1.255
• 192.168.1.128
• 192.168.1.100
• 192.168.1.0

Multiple Choice

In an IP address scope of 10.0.1.1-10.0.1.254 with a subnet of 255.255.255.0, what would the broadcast address be?

• 10.0.1.255
• 10.0.1.0
• 10.0.1.128
• 10.0.1.1

Multiple Choice

Why does the broadcast address always end with 255?

• The broadcast address ends with 255 because it represents all host bits set to 1 in the last octet of an IPv4 address.
• The broadcast address is used for unicast communication.
• The broadcast address is always the first address in the subnet.
• The broadcast address is determined by the subnet mask only.

Word Cloud

Name one thing you learned about IPv4

Word Cloud

Name one thing you learned about HOST ID

Word Cloud

Name one thing you learned about subnet masks