Networking Concepts to understand

• DHCP (Dynamic Host Configuration Protocol): DHCP server is responsible for assigning an ip address to the device connected to a network. DHCP can assign static ip to a device or a dynamic from free ip addresses available in network cidr range
  
• DNS Server: Networking protocols work with ip addresses, but ip addresses are not human friendly.
  • DNS(Domain Name Server) is about mapping a name and other information to an ip
  • DNS contains Records and Refer Here for record types. Lets focus on two record types A (Domain name to ip) and CNAME (alias to a domain)
  • DNS can be configured at client machine
    • windows C:\windows\system32\drivers\etc\hosts
    • *nix /etc/hosts
  • DNS can be configured at server end as well
    • public DNS
    • internal DNS
  • Public DNS:
    • We would have a DNS Zone where we will maintain the records of DNS Server
      

Communication between two private networks

• When you want to communicate between two private network CIDR Ranges should not be colliding

Case A:
Network A: 192.168.0.0/24 => 192.168.0.0 to 192.168.0.255
Network B: 192.168.1.0/24 => 192.168.1.0 to 192.168.1 255
Not colliding

Case B:
Network A: 192.168.0.0/24 => 192.168.0.0 to 192.168.0.255
Network B: 192.168.0.0/23 => 192.168.0.0 to 192.168.1.255
Colliding

Having some physical connectivity between them

• We have network connectivity between two networks, then we need to configure router rules to forward packets from one router to other
  
• Consider this as connectivity between two networks in same campus of your organization

Having no direct physical connectivity

• Consider this as a connectivity between two networks in two different cities
  • Leased Line
  • VPN
    
• Note: Work from home or Point to site VPN