VPC - Virtual Private Cloud Flashcards
What is VPC?
Amazon Virtual Private Cloud (Amazon VPC) lets you provision a logically isolated section of the AWS Cloud where you can launch AWS resources in a virtual network that you define
What is an Internet Gateway?
An internet gateway is a horizontally scaled, redundant, and highly available VPC component that allows communication between your VPC and the internet
What represents also an Internet Gateway for the instances that have a public IPv4?
a NAT
Does Internet Gateways guarantee on their own to access internet?
no, you must also edit Route tables, for Egress Only as well
What are Route Tables?
A route table contains a set of rules, called routes, that are used to determine where network traffic from your subnet or gateway is directed
What is a NAT Instance?
Use a NAT instance in a public VPC subnet to enable outbound internet traffic from instances in a private subnet. (OLD WAY, deprecated)
What is a NAT Gateway?
NAT Gateway is a highly available AWS managed service that makes it easy to connect to the Internet from instances within a private subnet in an Amazon Virtual Private Cloud (Amazon VPC). Previously, you needed to launch a NAT instance to enable NAT for instances in a private subnet
What is NACL?
A network access control list (ACL) is an optional layer of security for your VPC that acts as a stateless firewall for controlling traffic in and out of one or more subnets. You might set up network ACLs with rules similar to your security groups in order to add an additional layer of security to your VPC.
What is default NACL default behavior
allows everything inbound and ourbound
What is the relation cardinality between subnets and NACLs?
1 to 1, new Subnets are assigned the Default NACL
What are the characteristics of NACLs?
- Rules have a number (1-32766) and higher precedence with a lower number
- E.g. If you define #100 ALLOW and #200 DENY , IP will be allowed
- Last rule is an asterisk (*) and denies a request in case of no rule match
- AWS recommends adding rules by increment of 100
What is new NACLs default behavior
deny everything
What is VPC peering?
A VPC peering connection is a networking connection between two VPCs that enables you to route traffic between them using private IPv4 addresses or IPv6
How do instances communicate on VPC peering?
Instances in either VPC can communicate with each other as if they are within the same network
What must not have VPCs involved in VPC peering?
overlaping CIDR