1. IPv4 Addresses
A Quick Guide

2. What is an IPv4 Address 32 bits separated by 4 groupings of bits
32 bits = 2^32 possible = 4.2 Million IPv4 Addresses
Each octet can be up to 255
IP stands for Internet Protocol
IP is the primary set of rules that transport data
Network numbers are managed by ICANN

3. Where do you use IP addresses?
Everywhere
Computers, phones, light bulbs, even toothbrushes
Hunting
Finding the bad guy
Being the bad guy
Setting up networks
Technical exams

4. Classful IP Range

5. Special addresses Class Start Finish Class A Private 10.0.0.0
Class B Private
Class C Private
Loopback
APIPA

6. Private IP address Reusable Specific to individual networks
Companies, homes, and devices all have these same addresses

7. Loopback Often used for testing Can send signals back to the device
Allows an administrator to act as if the local machine was remote

8. APIPA Automatic Private IP Addressing
Ability to assign an IP address to a machine without an internet connection
Assigns default class B subnet
Computer can only communicate with nodes using APIPA range
Occurs when devices use DHCP (Dynamic Host Configuration Protocol) and no DHCP is available

9. What address are private?

10. Private IP address Class Start Finish Comment Class A 10.0.0.0
Class B
Class C
Loopback
Common
APIPA

11. Default Gateway Routers IP address
The destination gateway of all traffic
Connects different networks
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This Photo by Unknown Author is licensed under CC BY-ND

12. Subnetting Separates Network from host
IP Address
Subnet Mask
Subnetting
Separates Network from host
Network ID: identifies the network
Host ID: identifies the computer or device on the network
Series of flags that indicate the segmented network or LAN (Local Area Network) that contains the IP addresses
If the subnet mask has a 255 in the octet
Than the IP address must start contain the corresponding fields
Example: has 3 sets of For an IP address to be in the same subnet or segmented network, the IP address must start with

13. Does the traffic stay or go?
IP Address
Subnet
LAN Range X
IP Address
LAN
Gateway X
IP Address
LAN
Gateway

14. Changing Subnet The left side of the LAN Range is Networks
IP Address
Subnet
LAN Range X
X.X
192.X.X.X
The left side of the LAN Range is Networks
The right side of the LAN Range is Hosts
Changing the subnet mask increases or decreases the size of your subnet

15. Binary A bit is a 1 or a 0 Octet 1 = On 0 = Off 00000000 = 0
= 255

16. Does 192 go into 128? Yes, Put a 1 in the 128 network column
Try 5 and 2 on your own.
=64
Does 64 go into 64? Yes Put a 1 in network 64
64-64=0
The rest of the division will result in zeros
IP to Binary
128 64 32 16 8 4 2 1
Network
Class A
Class B
Class C
Does 168 go into 128?
Yes, Put a 1 in Class A
=40
Does 64 go into 40? No, put a zero in Class A under 64.
Does 32 go into 40? Yes
Place a 1 in Class A 32/
40-32=8
The only place 8 fits is 8.
Base Exponent: In binary, you can determine number if

17. Try 5 and 2 on your own.
Binary to IP
In the network row find your ones.
The ones are located in field 128 and 64
128+64=192
128 64 32 16 8 4 2 1
Network
Class A
Class B
Class C
In the Class A rown find your ones.
The ones are located in field 128, 32, 8
= 168
Base Exponent: In binary, you can determine number if

18. Subnetting Example Both IPs and Subnets are 32 characters
192
168 1 12 X
255
Both IPs and Subnets are 32 characters
Ways to write
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19. CIDR Classless Inter-Domain Routing Problem with Classful Why
Class A: 16,777,214 Hosts
Class B: 65,534 Hosts
254 Hosts
Why
Need smaller or larger networks
What if you needed a network for 1000 hosts, you would was 64,534 addresses
Or have 5 smaller networks
Easy to organize networks

20. VLSM Variable Length Subnet Mask
Using Binary you can choose where to separate the network from the hosts
Draw a line and choose your network, you are no longer restricted to 0 and 255
255 7
_____
248

21. CIDR with VLSM
192
168 1 12 X
255
252
You may not always want to use a full range of address
Note the 1’s all belong to the subnet and must match other IPs in the network
Ways to write
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There are two zeros at in the 3rd column separating network bits from host bits.. Take the last two digits of your IP address: 00 to 11 and calculate your range
Numbers
Binary 3rd column
Conversion
Minimum
Maximum 3

22. Speed Run
The Magic Box

23. Dotted Decimal Notation
Quick Draw IP Address
Network bits
This is the total number of networks you can have per CIDR or Dotted Decimal
Networks per Subnet 2 4 8 16 32 64
128
256
Dotted Decimal Notation
192
224
240
248
252
254
255
Hosts Per Subnet: Class C 1
Class A /9
/10
/11
/12
/13
/14
/15
/16
Class B
/17
/18
/19
/20
/21
/22
/23
/24
Class C
/25
/26
/27
/28
/29
/30
/31
/32
Dotted Decimal Notation
From the host bit take the Left most value, put it in dotted decimal spot, than take that number add it to the next host bit ex = 192, than add =224 and so on
HOST Bits
Double Numbers from right to left starting at 1
CIDR
Each row represents 8 binary bits, allowing you to see the Class breakdown
Base Exponent: In binary, you can determine number if
9 Columns by 6 Rows

24. Host bits start in the second Octet
Default Subnet Masks
Networks per Subnet 2 4 8 16 32 64
128
256
Dotted Decimal Notation
192
224
240
248
252
254
255
Hosts Per Subnet 1
Network.Host____.Host____.Host
Class A /9
/10
/11
/12
/13
/14
/15
/16
Network.Network.Host______.Host
Class B
/17
/18
/19
/20
/21
/22
/23
/24
Network.Network.__Network.Host
Class C
/25
/26
/27
/28
/29
/30
/31
/32
The First Octet is Reserved for the Network
Only Class A, Class B, and Class C have subnets
The host bits start on the 9th bit

25. How to Find CIDR Notation
Find the intersection between the subnet and Class. The point of intersection is the CIDR
How to Find CIDR Notation
Networks per Subnet 2 4 8 16 32 64
128
256
Dotted Decimal Notation
192
224
240
248
252
254
255
Hosts Per Subnet 1
Class A /9
/10
/11
/12
/13
/14
/15
/16
Class B
/17
/18
/19
/20
/21
/22
/23
/24
Class C
/25
/26
/27
/28
/29
/30
/31
/32
If the octet is all 1s. Is this is a network bit
You are given a subnet mask of , What is the CIDR Notation?
Network_.___A___.___B_____.___C____
Network_.Network.HostBits
Class A is the 2nd Octet
Class B is the 3rd Octet
Class C is the 4th Octet

26. How to Find Dotted Decimal
/14 is in the 6th Row, this means 6 bits are turned on
Networks per Subnet 2 4 8 16 32 64
128
256
Dotted Decimal Notation
192
224
240
248
252
254
255
Hosts Per Subnet 1
Class A /9
/10
/11
/12
/13
/14
/15
/16
Class B
/17
/18
/19
/20
/21
/22
/23
/24
Class C
/25
/26
/27
/28
/29
/30
/31
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CIDR /14 is in the Class A Range
If you are given a CIDR (Classless Inter-domain Routing) of /14, what is the subnet mask?
Find /14
Find the intersection of Dotted Decimal and the CIDR #
Network bits are always the 1st 8 bits
2nd Octet is Class A, The /14 is class A, place intersection in Class A octet. If the CIDR was class B you would use the 3rd octet and 4th for C

27. Hosts
Networks per Subnet A 2 4 8 16 32 64
128
256
Dotted Decimal Notation
192
224
240
248
252
254
255
Hosts Per Subnet: Class A
8,388,608
4,194,304
2,097,152
1,048,574
524,286
262,144
131,072
65,536
Hosts Per Subnet: Class B
32,768
16,384
8,192
4,096
2,048
1,024
512
Hosts Per Subnet: Class C 1
Class A /9
/10
/11
/12
/13
/14
/15
/16
Class B
/17
/18
/19
/20
/21
/22
/23
/24
Class C
/25
/26
/27
/28
/29
/30
/31
/32
Base Exponent: In binary, you can determine number if
/8=16,777,216

28. Exercise Use the box to determine Dotted Decimal Notation for /19?
What is the CIDR notation for 252?
How many hosts are in a /30?
If you have 4,096 hosts what is your CIDR notation?
If you have 32 networks what
is your class B CIDR?
224
A=/14, B=/22, C=/30
C=4, B=1024, A=262,144
C=/28, B=/20, A=/12 21

29. Questions