Virtual Private Cloud (VPC) Flashcards
(139 cards)
What does CIDR stand for?
Classless Inter-Domain Routing
a method for allocating IP addresses
CIDR - Classless Inter-Domain Routing
A CIDR consists of two components
Base IP
Subnet Mask
- Represents an IP contained in the range (XX.XX.XX.XX)
- Example:10.0.0.0,192.168.0.0,…
Base IP
- Defines how many bits can change in the IP
- Example:/0,/24,/32
- Can take two forms:
- /8ó255.0.0.0
- /16ó255.255.0.0
- /24ó255.255.255.0
- /32ó255.255.255.255
Subnet Mask
basically allows part of the underlying IP to get additional next values from the base IP
CIDR - The Subnet Mask
New EC2 instances are launched into the default VPC if no ______ is specified
subnet
Default VPC has Internet connectivity and all EC2 instances inside it have public ________ addresses
IPv4
Default VPC in new EC2 instances, we also get a public and a private ____________ names
IPv4 DNS
Can you have multiple VPCs in an AWS region?
YES (max. 5 per region – soft limit)
Max. CIDR per VPC is ______ , for each CIDR:
* Min. size is
* Max. size is
5
/28 (16 IP addresses)
/16 (65536 IP addresses)
Because VPC is private, only the ________ ranges are allowed:
* 10.0.0.0 – 10.255.255.255 (10.0.0.0/8)
* 172.16.0.0 – 172.31.255.255 (172.16.0.0/12)
* 192.168.0.0 – 192.168.255.255 (192.168.0.0/16)
Private IPv4
Your VPC CIDR should ________ overlap with your other networks
NOT
AWS reserves ______ IP addresses (first 4 & last 1) in each subnet
5
These 5 IP addresses are __________ for use and can’t be assigned to an EC2 instance
not available
What does IGW stand for??
Internet Gateway
- Allows resources (e.g., EC2 instances) in a VPC connect to the Internet
- It scales horizontally and is highly available and redundant
- Must be created separately from a VPC
- OneVPC can only be attached to one IGW and vice versa
Internet Gateway (IGW)
Internet Gateways on their own __________ allow Internet access
do not
We can use a ________ to SSH into our private EC2 instances
Bastion Host
The bastion is in the _______ which is then connected to all other ___________
public subnet
private subnets
Bastion Host security group must allow inbound from the internet on _________ from restricted CIDR, for example the public CIDR of your corporation
port 22
Security Group of the EC2 Instances must allow the Security Group of the Bastion Host, or the __________ of the Bastion host
private IP
What does NAT stand for?
Network Address Translation
- Allows EC2 instances in private subnets to
connect to the Internet - Must be launched in a public subnet
- Must disable EC2 setting: Source / destination Check
- Must have Elastic IP attached to it
- RouteTables must be configured to route traffic from private subnets to the NAT Instance
NAT Instance