Correct Answers: A and B.
The AWS Documentation mentions the following.
A security group acts as a virtual firewall for your instance to control inbound and outbound traffic.
When you launch an instance in a VPC, you can assign up to five security groups to the instance.
A network access control list (ACL) is an optional layer of security for your VPC that acts as a 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.Option C is incorrect since this is used to decide on the DNS servers for the VPC.
Option D is incorrect since this is used for routing traffic in the VPC.
For more information on VPC security groups and NACL's, please visit the below URL.
https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_SecurityGroups.html https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_ACLs.html
Sure, I'd be happy to explain the two layers of security provided by AWS in a VPC.
Amazon Virtual Private Cloud (VPC) is a logically isolated virtual network in the AWS Cloud where you can launch AWS resources such as Amazon Elastic Compute Cloud (EC2) instances, Amazon Relational Database Service (RDS) instances, and other services. VPC provides you with control over your virtual networking environment, including your own IP address range, subnets, route tables, and network gateways.
When it comes to securing EC2 instances within a VPC, AWS provides two layers of security:
- Security Groups
- Network Access Control Lists (NACLs)
A. Security Groups: Security Groups are the first layer of defense for your EC2 instances. They are virtual firewalls that control the inbound and outbound traffic for one or more instances. Security Groups are stateful, which means that if you allow inbound traffic, the return traffic is automatically allowed. You can create rules in Security Groups to allow traffic from specific IP addresses, CIDR blocks, or other Security Groups. You can also specify the protocols and ports to allow or deny traffic.
For example, you can create a Security Group that allows HTTP traffic (port 80) from the internet to your web server instances, but denies all other traffic. Similarly, you can create a Security Group that allows SSH traffic (port 22) only from your corporate IP address range to your database server instances.
B. Network Access Control Lists (NACLs): Network Access Control Lists (NACLs) are the second layer of defense for your EC2 instances. They are also virtual firewalls, but they operate at the subnet level, not at the instance level. NACLs are stateless, which means that if you allow inbound traffic, you must also allow the return traffic explicitly. NACLs have separate inbound and outbound rules, and you can create rules to allow or deny traffic based on IP addresses, CIDR blocks, protocols, and ports.
NACLs provide a coarse-grained control over traffic that flows in and out of your subnets. For example, you can create a NACL that allows HTTP traffic (port 80) from the internet to your web server subnet, but denies all other traffic. Similarly, you can create a NACL that allows SSH traffic (port 22) only from your corporate IP address range to your management subnet.
C. DHCP Options: DHCP Options provide configuration settings for instances that are launched in your VPC, such as domain name servers and domain search lists. While DHCP Options are important for networking in general, they do not provide any additional security mechanisms for your instances.
D. Route Tables: Route Tables are used to control the traffic between subnets in your VPC. While Route Tables are important for routing in general, they do not provide any additional security mechanisms for your instances.
In summary, AWS provides two layers of security for your EC2 instances within a VPC: Security Groups and Network Access Control Lists (NACLs). Security Groups operate at the instance level, while NACLs operate at the subnet level. Both Security Groups and NACLs allow you to control inbound and outbound traffic based on IP addresses, CIDR blocks, protocols, and ports.
