Networking Concepts

• DNS (Domain Name Server):
  • DNS provides services which includes names to ip addresses (Domain names)
  • DNS Servers can be
    • public
    • internal
  • DNS Servers will have different record types
    • A Record: name to ip mapping
    • CName Record: alias to name
    • other record types Refer Here
  • DNS can be setup on client system
    • windows: open c:\windows\system32\drivers\etc\hosts and entries
    • other: open /etc/hosts and entries
  • DNS Servers can help
    
  • DNS Servers will have DNS zones
  • DNS servers work on port 53

Communication between two networks privately

• while communicating between two networks privately their ip ranges should not collide.

Case: non-colliding
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

Case: colliding
network A: 192.168.0.0/23 => 192.168.0.0 to 192.168.1.255
network B: 192.168.1.0/24 => 192.168.1.0 to 192.168.1.255

Within same campus/site/datacenter

• Since the underlying network exists, we need to configure routing rules
  

Across Cities

Option 1: Leased lines

Option 2: VPN (Virtual Private Networks)

* Note: Point to site (Work from home connection)