What are private networks and public networks

• Private Network:
  • This is network of systems which is not accessible externally (over internet)
  • can be connected to internet
  • there are reserved ip ranges for private network
    • 192.168.0.0 to 192.168.255.255
    • 10.0.0.0 to 10.255.255.255
    • 172.16.0.0 to 172.31.255.255
• Public Network:
  • This is network of systems which is accessible externally (over internet)
  • it is connected to internet
  • other ips than defined above
• In cloud we always create private networks

How internet works for private networks

• Home network
  

Network principles

• All the devices in the same network can communicate with each other over unique ip address
• When systems communicate there are networking protocols which will enable the communication
  
• We have two models
  • OSI : This is theoritical model and is used as reference
  • TCP/IP
    
• Router is a device which can forward network packets from one network to another. Every Router will have rules which are generally referred as route tables
• DNS (Domain Naming System) is responsible for resolving names
• Concepts:
  • Routing
  • DNS
  • SSL/TLS (https)