1. 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

2. 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

3. How to Find CIDR Notation
Find the intersection between the subnet and Class. The point of intersection is the CIDR
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 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
The octet is not complete in the 3rd Octet, therefor this is a Class B address

4. 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
/32
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 2nd octet and 3rd for C