AWS Classroom notes 20/Oct/2023

Networking contd

Scenario

• Design a private network with 16 subnets with each subnet of size 60 devices
• Network

2^n -2 ~= 960
n = 10
N = 22

CIDR: 192.168.0.0/22

• Subnet

2^n -2 ~= 60
n = 6
N = 32 -6 = 26

• subnetting

Network SM: 11111111.11111111.11111100.00000000
subnet  SM: 11111111.11111111.11111111.11000000
-------------------------------------------------
                 192.     168.000000yy.yy000000
                 192.     168.00000000.00000000 = 192.168.0.0/26
                 192.     168.00000000.01000000 = 192.168.0.64/26
                 192.     168.00000000.10000000 = 192.168.0.128/26
                 192.     168.00000000.11000000 = 192.168.0.192/26
                                                = 192.168.1.0/26
                                                = 192.168.1.64/26
                                                  192.168.1.128/26
                                                  192.168.1.192/26
                                                  192.168.2.0/26
                                                    192.168.2.64/26
                                                    192.168.2.128/26
                                                    192.168.2.192/26
                                                    192.168.3.0/26
                                                    192.168.3.64/26
                                                    192.168.3.128/26
                                                    192.168.3.192/26

NAT

• Network address Translation(NAT) is required to provide internet access to private networks
  
• NAT translates the source in the packet for outgoing traffic and translates destination for incoming packets.
• NAT conditions:
  • It should have public ip and should be connected to public network

DNS (Domain Naming Server)

• We need ip addresses for low level communications, our system will reach out to some servers to figure out ip addresses
• The server which respond to these requests are called as Name Servers
• We have nameservers by connection type located
  • in the same system
    • windows: C:\windows\system32\drivers\etc\hosts
    • linux: /etc/hosts
  • in your organization (internal/private)
  • from anywhere (external/public)
• DNS Record Types: Refer Here
• How DNS Works