Networking - VPC Flashcards
What are the 3 common private IP ranges?
10.0.0.0
172.16.0.0
192.168.0.0
What is the maximum number of VPCs allowed per region?
5
How many different CIDRs can you have per VPC?
5
How many addresses does Amazon reserve in each subnet’s range?
5
What is the suffix for the IP address that is the broadcast address in a subnet?
.255
What does an internet gateway do?
Allows resources in a VPC to connect to the internet
What is a bastion host?
An EC2 instance in a public subnet that allows users to connect to private instances with SSH from a public place.
Normally allows connection access from the public CIDR of your organisation (NOT everyone)
What is a NAT instance?
A routing server that sends traffic from private EC2 instances onwards to the internet from a public subnet.
What are the downsides of a NAT instance?
It is not highly available and resilient out of the box
Have to manage the associated security groups and rules
What other service does a NAT gateway require to perform its function?
An internet gateway
What is a NAT gateway?
An AWS managed NAT service that has high availability, bandwidth and no requirement for an admin management out of the box
At what level do NACLs exist?
The subnet level
At what level do security groups exist?
The specific instance level
Which of NACLs and security groups have both allow and deny rules?
NACLs
Which of NACLs and security groups have rules that are evaluated in order?
NACLs
What is VPC peering?
When two VPCs are connected privately through the AWS network, making them behave as if they were part of the same single VPC
Is VPC peering transitive? What does this mean?
No. This means that if A and B are peered, and B and C are peered, A cannot connect to C ‘through’ B.