AWS VPC Contd..

• All the subnets in the AWS VPC are private by default, they dont have internet access.
• The internet access can be enabled to the vpc by using internet gateway. Now the route table entry has to be added to forward the network packets to internet gateway.
  
• Create a vpc and verify for the existence of the default route table.
• This default route table allows all the traffic with in vpc.
  
• Lets create a internet gateway
  
  
  
  
• The ip address restrictions in cidr notation

10.10.0.0/16 => 10.10.x.x (specific network)

10.10.0.5/32 => 10.10.0.5 (specific ip)

0.0.0.0/0 => x.x.x.x (Any ip)

• Lets add a route between route table and igw for internet access
  
• Route table can be associated to the subnet. The default route table will act as a route table for all the subnets which are not associated to a specific route table.
  
• Public Subnet: A subnet which can access internet and can be accessed from internet
• Private Subnet: A subnet which cannot be accessed from internet.
• A subnet can be made public if it is associated with route table which has access to internet gateway and private if not.
• Lets create a new route table in the vpc
  • private rt
    
  • public rt
    
• Subnets can be made public by associating with public route table
  
  
  
  
• Now lets create an ec2 instance in public subnet
  
• Try to login using ssh command => It should allow
• Create an ec2 instance in private subnet, enable public ip (for testing) & try to login using ssh command => connection is timed out.
• Try to create the following from AWS CLI
  • VPC
  • 2 subnets
  • create internet gateway and attach to vpc
  • Create a public rt
  • Create a private rt