MultiCloud Classroom notes 30/Nov/2025

Public Networks vs Private Networks

• A public network is directly accesible over internet
• A private network is not directly accessible over internet.
  • For private networks we have reserved ip ranges
    • 192.168.0.0/16 => 192.168.0.0 to 192.168.255.255
    • 172.16.0.0/12 => 172.16.0.0 to 172.31.255.255
    • 10.0.0.0/8 => 10.0.0.0 to 10.255.255.255

How Private networks can access internet

• NAT
  

Subnetting

• private network cidrs

192.168.0.0/16
172.16.0.0/12
10.0.0.0/8

Example 1

• I need a create a network for 1000 devices and then we need to create two subnets
• Approach: First find host id bits for network and then subnet

Network
2^n - 2 = 1000
n = 10
N = 22
range: 192.168.0.0/22

Network SM:  11111111.11111111.11111100.00000000

• Subnet

2^n ~= 500
n = 9
N = 32 - 9 = 23

Subnet SM: 11111111.11111111.11111110.00000000

• NOw combine

ip:               192.     168.       0.       0/22
Network SM:  11111111.11111111.11111100.00000000
Subnet SM:   11111111.11111111.11111110.00000000
----------------------------------------------------
                                     x
                   192.    168.000000x0.0
                       192.168.00000000     => 192.168.0.0/23
                       192.168.00000010     => 192.168.2.0/23

Network: 192.168.0.0/22
subnet1 : 192.168.0.0/23
subnet2 : 192.168.2.0/23

Example 2

• I need a create a network for 6000 devices and then we need to create two subnets
• Network

2^n ~= 6000
n = 13
N = 32 - 13 = 19

Network: 192.168.0.0/19
Network SM: 11111111.11111111.11100000.00000000

• Subnet

2^n ~= 3000
n = 12
N = 20

Subnet SM: 11111111.11111111.11110000.00000000

• Combine

ip:              192.     168.       0.       0
Network SM: 11111111.11111111.11100000.00000000
Subnet SM:  11111111.11111111.11110000.00000000
   -----------------------------------------------
                 192.     168.000x0000.0
                 192.     168.00000000.0
                 192.     168.00010000.0
subnet 1: 192.168.0.0/20
subnet 2: 192.168.16.0/20

Exercise

• I need a create a network for 100 devices and then we need to create two subnets