AWS Virtual Private Cloud Fundamentals

Understanding AWS VPC: The Basics ??

Hey everyone! After a week break for my 30th, I've continued my studies for the AWS Solutions Architect certification.

Adrian Cantril's course takes a long detour shortly after starting into another course about tech fundamentals. I had considered writing articles on what I was learning there, but figured it would be best to discuss how those themes relate back to AWS as I come across them again during the course.

One of the fundamental topics I've studied in the last few days is the AWS Virtual Private Cloud (VPC). It's pretty fascinating, and I thought it might be helpful to write about it for others who are also learning or interested in AWS, and even as revision notes for myself. I'm excited to learn about in more in-depth as the course goes on.

What is an AWS VPC? ??

An AWS VPC lets you create a private network within the AWS cloud, similar to having your own data center but using AWS's infrastructure. In a VPC, you can launch AWS resources like EC2 instances and RDS databases and have control over your network settings, including IP address ranges, subnets, route tables, and gateways.

Default VPC vs. Custom VPC

When you first create an AWS account, AWS automatically sets up a default VPC in each region. It's ready to use right away, which is great for getting started quickly. But there's also the option to create a custom VPC, which offers more flexibility and control.

The default VPC is regionally resilient. This means that it would take every Availability Zone (AZ) in an AWS region to fail in order for the VPC to go down. The VPC is divided into subnets, each AZ having one and being allocated part of the VPC IP CIDR range for communication.

You can only have one default VPC per AWS region. This is because each default VPC uses the same CIDR range. This is a range of IP addresses which the VPC uses to communicate.

For the default VPC, this will always be 172.31.0.0/16. This notation means that the VPC's IP range starts at 172.31.0.0 and can use up to 65,536 IP addresses.

Benefits of the Default VPC:

• Pre-configured: Comes with a default subnet, route table, internet gateway, and security group. As a result, it can be less flexible.
• Ready to use: Easy to launch instances without setup.
• Public IP addresses: Instances in the default VPC often get public IP addresses automatically.
• Regionally Resilient: All AZs would have to go down for it to fail.

Custom VPC

The custom VPC on the other hand is exactly as it says, a custom solution. Any serious cloud system will make use of custom VPCs as they are much more flexible and can be tailored to the client's needs.

Benefits of the Custom VPC:

• Customized setup: Design your network to meet specific needs.
• Better security: More control over inbound and outbound traffic.
• Network segmentation: Create multiple subnets (public and private) for different parts of your application.

Why Not Just Use the Default VPC? ??

While the default VPC is convenient, it's not the best practice for long-term or production use.

Here’s why:

• Security: Default VPCs have a more open security setup. Custom VPCs let you enforce stricter security rules.
• Control: Custom VPCs give you more detailed control over your network settings, which is crucial for meeting specific organizational or industry requirements.
• Scalability: Custom VPCs support more complex setups, like multi-tier applications or connecting your AWS resources with on-premise systems.
• Isolation: With custom VPCs, you can create public and private subnets to keep sensitive data and critical applications separate from the internet.

In summary, while the default VPC is a good starting point, creating a custom VPC can provide better security, control, and scalability for your AWS environment. It's been really interesting learning about this, and I hope this breakdown is helpful for anyone else on their AWS journey! ??

Feel free to connect or reach out if you have any questions or just want to share your own AWS learning experiences! ??

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