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