Virtual Private Cloud

If cloud provide network in respective service that is known as Network As A Service(NAAS).NAAS is a part of Infrastructure As A Service(IAAS).

In AWS that service is known as VPC(Virtual Private Cloud).

In OpenStack it is known as Neutron. In earlier version it was known as Quantum.

Lets take an example of a company, that company wants to run some application and for they require servers i.e. environment(physical hardware,operating system, webserver). They have to put these servers in some labs where switches and routers are available. These labs consists of some machines having some apps to run,network card,switch and routers for connectivity).

Machines,routers,DHCP connected to the switches have same network name .DHCP server is the one who gave a unique IP dynamically when a new instance launch.

VPC is the network which keeps our infrastructure isolated from outside world. Known as virtual as it provide virtual space to create infrastructure which looks like real.

In VPC ,lab is known as Subnet.

For security of labs we have to add a rule or firewall outside the lab-Network Access Control LAN.

While creating account AWS create a default VPC for our system having 3 labs or subnets. And every subnet have DHCP server.

Creating VPC:

To create VPC: Services → VPC

Then in VPC go to YOUR VPC and then create VPC

--for creating VPC we have to give name, IP range.

Our VPC is created. Now there is no subnet in our VPC so we have to choose our vpc and create subnets.

Creating Subnet:

To create subnet we have to choose availability zone:

As we chose 256 IPs , got 251 as 5 are reserved IPs. While creating an instance if we choose this VPC then we will not be able share connectivity as that instance will not have public IP.So we have to add one public facing router.

Router having public IP looks like instance have public IP but that IP belongs to Router. Whenever we launch a new instance they add a public IP to Router and this is known as Internet Gateway.

In one VPC we have one internet gateway.If no internet gateway,then no public IP.

Creating Internet Gateway:-

To create gateway just give a name .

At this time this gateway is detached that is not connected to any VPC. So we have to attach it with our create VPC.

Auto assign IP : It assign public IP and start DNATing. So we have to enable this in subnet.

When we connect to some system , packet reached from one system to another . But if target system won’t accept that packets then connectivity will never establish. To resolve this we have to create routing table to add internet gateway details.

Creating Routing Table:-

For doing this automatic we have to update DHCP server so that whenever instance wants to connect other ,it can respond easily.

We can also add DNS Hostname to VPC:

Now when we launch instance we have to add our vpc and subnet.

Here our instance have public IP ans DNS name.

Thank You!!!!