Azure Networking Contd…

• A virtual network address spaces can be extended i.e.
  • we created a virtual network with address space 192.168.0.0/24
  • If we need more ips in the same network any time after creation you can add new cidr range and assign this to subnets. lets add 192.168.100.0/24
    
    
    
• Subnets address space can be edited but the interfaces (nic) which are already in use will still be part of the same subnet.
• Any subnet we create in Azure would reserve 5 ip addresses
  • x.x.x.0 => Network id (Any network)
  • x.x.x.1 => Default gateway (Azure)
  • x.x.x.2, x.x.x.3 => Azure DNS (Azure)
  • x.x.x.255 => Network Broadcast ip (Any Network)

Network Security Group

• This is used to restrict network packets
• This can be assigned to
  • Network Interface (nic)
  • subnet
• NSG whenever a packet arrives (assuming ingress)
  • verifies the packet against the rules by priority
• NSG Has default rules
  • Incoming (ingress):
    • Packet with source from same vnet allow this
    • Packt from Azure load balancer => Allow this
    • Deny rest
  • Outgoing (egress):
    • Allow to any destination.
• When we create NSG if we want the above behavior there is no need to add any rules but if you need to allow/deny some packet or make changes, we add security rules which are processed in priority
  
• Next Steps:
  • NSG’s at subnet level and NIC Level