20 AWS Security Group Interview Questions and Answers

AWS Security Groups are an important part of Amazon Web Services, providing security for AWS resources. If you’re applying for a position that involves AWS, you’re likely to be asked questions about Security Groups during the interview process. In this article, we’ll review some of the most common questions about Security Groups so that you can be prepared for your next interview.

AWS Security Group Interview Questions and Answers

Here are 20 commonly asked AWS Security Group interview questions and answers to prepare you for your interview:

1. What is an AWS Security Group?

A security group is a virtual firewall that controls the inbound and outbound traffic for your EC2 instances. When you launch an instance, you associate one or more security groups with the instance. You add rules to each security group that control the traffic that is allowed to reach your instance.

2. Can you explain what a security group is in the context of AWS services?

A security group is a virtual firewall that controls the traffic for one or more AWS instances. When you launch an instance, you associate one or more security groups with the instance. You add rules to each security group that control the inbound and outbound traffic for the instance. You can modify the rules for a security group at any time; the new rules are automatically applied to all instances that are associated with the security group. When you no longer need a security group, you can delete it.

3. How can you create a new security group in AWS?

You can create a new security group in AWS by going to the EC2 console, selecting the “Security Groups” link in the sidebar, and then clicking the “Create Security Group” button.

4. What do you understand about outbound and inbound rules in the context of AWS security groups?

Outbound rules are the rules that are applied to allow traffic to leave a particular security group, while inbound rules are the rules that are applied to allow traffic to enter a particular security group. Inbound rules are generally more restrictive than outbound rules, since it is generally more important to control what is coming into a system than what is leaving it.

5. What’s the best way to assign multiple IP addresses to a single instance using security groups?

You can use Amazon’s EC2 security groups to allow multiple IP addresses to access a single instance. To do this, you will need to create a security group and add each IP address that you want to allow access to the group. You can then assign the security group to your instance.

6. Can you give me some examples of situations where it makes sense to use separate security groups for different instances?

There are a few reasons you might want to use separate security groups for different instances. One reason is if you want to have different security policies for different types of instances – for example, you might want to have a more restrictive security policy for database servers than for web servers. Another reason is if you want to isolate different parts of your infrastructure for security purposes – for example, you might want to put all of your database servers in one security group so that they can communicate with each other, but you might want to put your web servers in a different security group so that they can’t directly access your database servers.

7. Can you explain what Amazon VPC security groups are?

Amazon VPC security groups are virtual firewalls that control the traffic for one or more Amazon EC2 instances. When you launch an instance, you can associate one or more security groups with the instance. You add rules to each security group that control the inbound and outbound traffic for the instance. You can modify the rules for a security group at any time; the new rules are automatically applied to all instances that are associated with the security group. When you create a security group, you specify a name and a description for the security group.

8. Are there any limitations on the number of security groups that can be created per region or account? If yes, then what are they?

Yes, there are limitations on the number of security groups that can be created per region or account. The maximum number of security groups that can be created per region is 100, and the maximum number of security groups that can be created per account is 500.

9. Is it possible to modify a security group after its creation? If yes, then how?

Yes, it is possible to modify a security group after its creation. You can do this by going to the AWS Management Console, selecting the security group that you want to modify, and then making the necessary changes.

10. Is it possible to delete a security group from your EC2 console? If yes, then how?

Yes, it is possible to delete a security group from your EC2 console. To do so, simply select the security group you wish to delete and then click the “Delete” button.

11. What happens if two security groups have conflicting rules for a single port?

If two security groups have conflicting rules for a single port, then the security group with the more restrictive rule will take precedence.

12. How does the order of rules in a security group affect its behavior?

The order of the rules in a security group is important because it determines how the traffic is filtered. The rules are processed in order, and if a packet does not match the criteria of a rule, it is then passed on to the next rule. This process continues until the packet either matches a rule or is dropped.

13. What is the difference between Classic and Default VPCs with respect to security groups?

The main difference between Classic and Default VPCs with respect to security groups is that Classic VPCs do not support automatic assignment of public IP addresses to instances, while Default VPCs do. This means that, in a Classic VPC, you will need to manually assign a public IP address to each instance you create, while in a Default VPC, each instance will be automatically assigned a public IP address. This can impact the security of your instances, as instances in a Classic VPC will be less accessible from the Internet than those in a Default VPC.

14. When creating a new rule in an AWS security group, which among these parameters is mandatory: source, destination, or protocol?

The protocol parameter is mandatory when creating a new rule in an AWS security group. The source and destination parameters are not mandatory, but they are recommended in order to help specify the traffic that is allowed by the rule.

15. Is it possible to add more than one CIDR block as a source IP address for a security group?

Yes, it is possible to add more than one CIDR block as a source IP address for a security group. You can do this by creating multiple inbound rules, each with a different CIDR block as the source.

16. How long does it take for changes made to a security group to get reflected in terms of network traffic?

The changes made to a security group are usually reflected within a few minutes. However, it can take up to an hour for the changes to be fully propagated.

17. What’s the maximum size of a packet allowed while creating a new rule in a security group?

The maximum size of a packet allowed while creating a new rule in a security group is 576 bytes.

18. What’s the default limit on the number of security groups that can be used by each instance?

The default limit on the number of security groups that can be used by each instance is 5.

19. What’s the default limit on the number of security groups that can be associated with each instance?

The default limit on the number of security groups that can be associated with each instance is 5.

20. What’s the maximum number of rules that can be present in a security group?

The maximum number of rules that can be present in a security group is 100.