AWS Networking Services Flashcards
What is Amazon Virtual Private Cloud (VPC)?
A virtual private cloud (VPC) is a virtual network dedicated to your AWS account.
It is logically isolated from other virtual networks in the AWS Cloud.
VPC Diagram
Subnet reside in Availability Zone
Multiple AZs reside in VPC
One VPC in a region
Router on AZ level
Internet Gateway on VPC level
Route table used to configure VPC router
What must you specify when you create a VPC?
When you create a VPC, you must specify a range of IPv4 addresses for the VPC in the form of a Classless Inter-Domain Routing (CIDR) block; for example, 10.0.0.0/16.
This is the primary CIDR block for your VPC.
What does VPC allow control of?
Provides complete control over the virtual networking environment including selection of IP ranges, creation of subnets, and configuration of route tables and gateways.
You can create your own IP address ranges, and create subnets, route tables and network gateways.
You can launch your AWS resources, such as Amazon EC2 instances, into your VPC.
You have full control over who has access to the AWS resources inside your VPC.
What AZs does a VPC span across in a region?
A VPC spans all the Availability Zones in the region.
Is default VPC created upon AWS account creation?
When you first create your AWS account a default VPC is created for you in each AWS region.
Where are default VPCs created in a region?
A default VPC is created in each region with a subnet in each AZ.
How many VPCs can be created in a region?
By default you can create up to 5 VPCs per region.
Is it possible to specify instances to launch on dedicated hardware in a VPC?
You can define dedicated tenancy for a VPC to ensure instances are launched on dedicated hardware (overrides the configuration specified at launch).
Does default VPC have all public subnets?
The default VPC has all-public subnets.
What are public subnets in VPCs?
Public subnets are subnets that have:
- “Auto-assign public IPv4 address” set to “Yes”.
- The subnet route table has an attached Internet Gateway.
What IP addresses does an instance in a VPC have?
Instances in the default VPC always have both a public and private IP address.
How are AZ names mapped in a VPC?
AZs names are mapped to different zones for different users (i.e. the AZ “ap-southeast-2a” may map to a different physical zone for a different user).
What are the components of a VPC?
A Virtual Private Cloud Subnet Internet Gateway NAT Gateway Hardware VPN Connection Virtual Private Gateway Customer Gateway Router Peering Connection VPC Endpoints Egress-only Internet Gateway
VPC Component: Virtual Private Cloud
A Virtual Private Cloud: A logically isolated virtual network in the AWS cloud. You define a VPC’s IP address space from ranges you select.
VPC Component: Subnet
Subnet: A segment of a VPC’s IP address range where you can place groups of isolated resources (maps to an AZ, 1:1).
VPC Component: Internet Gateway
Internet Gateway: The Amazon VPC side of a connection to the public Internet.
VPC Component: NAT Gateway
NAT Gateway: A highly available, managed Network Address Translation (NAT) service for your resources in a private subnet to access the Internet.
VPC Component: Hardware VPN Connection
Hardware VPN Connection: A hardware-based VPN connection between your Amazon VPC and your datacenter, home network, or co-location facility.
VPC Compnent: Virtual Private Gateway
Virtual Private Gateway: The Amazon VPC side of a VPN connection.
VPC Component: Customer Gateway
Customer Gateway: Your side of a VPN connection.
VPC Component: Customer Gateway
Customer Gateway: Your side of a VPN connection.
VPC Component: Router
Router: Routers interconnect subnets and direct traffic between Internet gateways, virtual private gateways, NAT gateways, and subnets.
VPC Component: Peering Connection
Peering Connection: A peering connection enables you to route traffic via private IP addresses between two peered VPCs.
VPC Component: VPC Endpoints
VPC Endpoints: Enables private connectivity to services hosted in AWS, from within your VPC without using an Internet Gateway, VPN, Network Address Translation (NAT) devices, or firewall proxies.
VPC Egress-only Internet Gateway
Egress-only Internet Gateway: A stateful gateway to provide egress only access for IPv6 traffic from the VPC to the Internet.
What are the options to securely connect to VPN?
AWS managed VPN – fast to setup.
Direct Connect – high bandwidth, low-latency but takes weeks to months to setup.
VPN CloudHub – used for connecting multiple sites to AWS.
Software VPN – use 3rd party software.
What is an ENI in VPC?
An Elastic Network Interface (ENI) is a logical networking component that represents a NIC.
ENIs can be attached and detached from EC2 instances, and the configuration of the ENI will be maintained.
What are Flow Logs in VPC?
Flow Logs capture information about the IP traffic going to and from network interfaces in a VPC.
Flow log data is stored using Amazon CloudWatch Logs.
Where can Flow Logs be created?
Flow logs can be created at the following levels:
- VPC.
- Subnet.
- Network interface.
How can peering connections be created?
Peering connections can be created with VPCs in different regions (available in most regions now).
What is the process of adding subnet in a VPC?
After creating a VPC, you can add one or more subnets in each Availability Zone.
When you create a subnet, you specify the CIDR block for the subnet, which is a subset of the VPC CIDR block.
What geographical restrictions does subnets have in VPCs?
Each subnet must reside entirely within one Availability Zone and cannot span zones.
What different types of subnets are there in VPC?
- public subnet
- private subnet
- VPN only subnet