VPCs Flashcards
What does VPC stand for?
Virtual Private Cloud
What is a VPC?
- Think virtual data center in the cloud
- A logically isolated section of AWS where you can launch AWS resources in a virtual network that you define
What can you do with a VPC?
- Launch instances into a subnet of your choosing
- Assign custom IP address ranges in each subnet
- Configure route tables between subnets
- Create Internet Gateway and attach it to our VPC
- Much better security control over your AWS resources
- Instance security groups
- Subnet Network Access Control Lists
What is VPC Peering?
- Allows you to connect one VPC with another via a direct network route using private IP addresses
- Instances behave as if they were on the same private network
Can VPC Peering be done between two VPCs in different AWS accounts?
Yes
Suppose VPC A is peered with VPC B, and VPC B is paired with VPC C. Is VPC A considered peered with VPC C?
NO. VPC Peering is NOT transitive!
Can you use VPC Peering to peer two VPC in different AWS regions?
Yes
What does IGW stand for?
Internet Gateway
What are the key components of a VPC?
- Gateway (IGW or Virtual Private Gateway)
- Route Tables
- Network Access Control Lists
- Subnets
- Security Groups
Can you have two VPC subnets in the same AZ?
Yes
Can you have a subnet stretched across multiple AZs?
No
When you create a VPC, what infrastructure is created by default?
- A Default Route Table
- A Network ACL
- A Default Security Group
(Note that it does NOT create subnets or IGWs)

If I launch a VPC into US-East-1a in my account, and someone else launches a VPC into US-East-1a in their account, does this mean the two VPCs are in the same AZ?
Not necessarily, The AZ’s are randomized
How many IP Addresses does Amazon Reserve per subnet?
5
What is the maximum number of IGWs you can have per VPC?
1
Can you have a security group spanning multiple VPCs?
No
Can you create an ELB with only one public subnet?
No, to create an ELB you need at least 2 public subnets
What is a Bastion Host?
A hardened, secure request forwarder allowing you to SSH/RDP in to private subnets in order to administer them (Idea is about lowering surface area of attack)
Can you use a NAT Gateway as a Bastion Host?
No
Are Bastion Hosts usually placed in a private subnet or a public subnet?
They are placed in a public subnet so you can access the private subnet
What is Direct Connect and what are its primary use cases?
- Idea is that it directly connects your data center to AWS
- Useful for high throughput workloads (lots of network traffic)
- Useful if you need a stable and reliable secure connection
What are the steps for setting up AWS Direct Connect?
- Create a virtual interface in the direct connect console. This is a PUBLIC virtual interface
- Go to the VPC Console and then to VPN Connection. Create a Customer Gateway
- Create a Virtual Private Gatway
- Attach the Virtual Private Gateway to the desired VPC
- Select VPN Connections and create a new VPN Connection.
- Select the Virtual Private Gateway and the Customer Gateway
- Once the VPN is available, set up the VPN on the customer gateway or firewall
What is AWS Global Accelerator?
A service in which you create accelerators to improve availability and performance of your applications for local and global users
How many static IP addresses does AWS assign to you for Global Accelerator?
2
(Note you can also bring your own static IPs!)
