4.4-Virtual Private Cloud - Default VPC

Quick overview 🚁

This is mostly Tech blurb...

If you want to skip, jump to "Default VPC"

A VPC is a set of private IP networks all part of the same private "address space" that belongs to you :

• in one AWS Region (Stockholm : eu-north1)

• spread over several AZs = AWS "Availability Zones" (Stockholm : 3 AZs = eu-north-1a/1b/1c)

• sharing some of their security and network settings

• with or without public IPs attached to the servers in the networks

The "private address space" mentioned above means that all your networks in a VPC will be part of a contiguous large range of private IP addresses belonging to you (recently added AWS feature : you can now even add more ranges of private IPs if the first one is not enough)

The VPC private IP range is a block (of max. "/16" = 64K = 65536 IPs) contained within one of these :

• 192.168.0.0 to 192.168.255.255, which is noted 192.168.0.0/16 (that's called a "CIDR block")

• 172.16.0.0 to 172.31.255.255, which is noted 172.16.0.0/12

• 10.0.0.0 to 10.255.255.255, which is noted 10.0.0.0/8

An AWS Region is made of several AZs = AWS Availability Zones which you can consider as multiple distinct datacenters, near enough each other that they are all interconnected on VERY high speed optical fiber connections.

So a VPC in one region is split in multiple interconnected IP "sub-networks" (at least 1 for each AZ). When you create a VPC, you can also choose to split it into more subnets, each with some specific characteristics :

• with/without Internet access

• reachable from the Internet, or not (servers also get a public IP, or they don't)

• etc...

If you want to know more about AWS VPCs, please browse the docs.

Default VPC

When you created your AWS account, your were automatically provided with a Default VPC in each region, and you can see how it is defined in the "VPC Console" (in the Networking & Content Delivery section).

We'll use a very basic setup, relying on the Default VPC that AWS automatically provides for you in any AWS Region.

This default AWS VPC in your region of choice perfectly fits the bill to host our lonely little OpenVPN server, so we'll use it "as is".

For the moment, just use the "VPC Console" to...

take a quick look at your default VPC and make a note of its private IPv4 block :

Note your Default VPC IPv4 CIDR block