New VPC Creation

 Create VPC Steps

Step1: Given CIDR 10.0.0.0/24 that means 32-24(8) =power(2,8)=256 Ip's

Step2:

Click Create VPN

After created VPC default one security group and one Route tables created automatically

Step3:Now we need divide the VPC IP's to subnets Public and private for dividing subnets,we have give CIDR range for them separately 

Step4:Create Subnets

  Goto subnet>Click create subnet

• Select you VCP which created early yar ,every region has 3 available zones (i,e datacenter) you can choose any if not it will take automatically,
• For subnet we need give ip address range(CIDR) 10.0.0.0 /24 (16-32 rage) (32-24)=8   2 power of 8 =256 IP’s
• Need to CIDR range for the subnet ip’s which is you go to divide the subnet public and private
• Netmask: 25 equal shared public and private 

 Created one Subnet as public name

as see here CIDR range block public subnet 128 Ip's automatically splitted

Create one more subnet Private, give same CDIR range for private subnet you see below screen shot getting error  subnet previous we have given public subnet 10.0.0.0/25,  that means

We have these ip for public subnet 10.0.0.0.. 10.0.0.128 reserved ,now already occupied for them,

So we need give different range 10.0.0.128..10.0.0.256

After change CIDR range 10.0.00.128/24 automatically created  Private subnet,Please find the screen shot below

 We have created 256 IP Private subnet(128),Public subnet(128) 

As we see above Available Ips address assigned 123 only128-5(5 was reduced, by Aws for internal requirement in each subnet ,those are all first 4 and last one ip’s) remaining showing 123 available