Enhancing Security in AWS Elastic Beanstalk: A Comprehensive Guide to Whitelisting IPs and Subnets (CIDR block)

In today’s digital landscape, security remains a paramount concern for businesses and organizations deploying their applications to the cloud. AWS Elastic Beanstalk, a fully managed platform as a service (PaaS) that streamlines the deployment of applications, offers various tools to fortify the security of your applications. One essential security practice is whitelisting IPs and whole subnets with CIDR blocks, a process like a virtual doorman, allowing only trusted entities to access your applications. In this comprehensive guide, we will dive into the significance of this practice, the steps to implement it, and provide real-world examples to solidify your understanding.

Importance of Whitelisting IPs and Subnets

Whitelisting IPs and subnets in AWS Elastic Beanstalk are like implementing a digital fortress around your application. It restricts access to a predetermined list of IP addresses or subnets, thereby significantly reducing the attack surface and preventing potential threats. Consider the analogy of a secure building – only individuals with an authorized key card can enter. Similarly, only designated IP addresses or subnets can access your application, minimizing the risk of unauthorized access, data breaches, and potential downtime. Additionally, implementing IP whitelisting complements other security measures, contributing to a layered defense strategy. While Virtual Private Networks (VPNs) provide a secure channel for remote access, whitelisting enhances this by ensuring that even if someone gains VPN access, they still need to be on a trusted network to reach your application. 

Step-by-Step Guide to Whitelisting IPs and Subnets (with CIDR blocks) 

1. Navigate to Elastic Beanstalk Environment: 

Log in to your AWS Management Console, navigate to the Elastic Beanstalk service, and select the environment you want to secure.

2. Access Security Groups:

Within the environment dashboard, locate the “Configuration” section and click on the “Edit” button next to the “Instance traffic and scaling” card.

Here, you can make a note of the instances’ load balancer security group.

Next, head over to the EC2 dashboard and locate “Security Groups” section under Network & Security.

3. Modify Inbound Rules:

In the security group settings, access the “Inbound rules” section. Here, you can specify the IP addresses or CIDR blocks that are allowed to access your application.

4. Add Whitelisted IPs/Subnets:

Click on “Add rule,” and in the rule editor, select “HTTP” and “HTTPS” as the type. Then, choose “Custom” in the “Source” column and enter the IP address or subnet in CIDR notation. You can add multiple entries as needed. 

5. Apply Changes:

After adding the desired IP addresses and subnets, save the changes to the security group.

Examples for Context

1. Single IP Whitelisting: Imagine you have a partner company that needs access to a specific environment for collaborative purposes. By whitelisting their IP address (e.g.,, you ensure they can connect securely without exposing your application to potential threats. In a broad sense, when we refer to “/32,” it indicates that the network encompasses just a solitary IPv4 address. Consequently, all communication occurs exclusively between the device linked to that IPv4 address and the default gateway. In this context, the default gateway corresponds to the AWS network.

2. Subnet Whitelisting: In cases where you have a dedicated development team working from a corporate subnet (e.g.,, you can whitelist the entire subnet. This way, your team can access the environment without individually specifying each team member’s IP.


Securing your AWS Elastic Beanstalk environment through IP and subnet whitelisting is a crucial step toward safeguarding your applications from potential threats. By allowing only trusted entities to access your resources, you create a robust defense mechanism that complements other security measures. This practice not only reduces the attack surface but also aligns with the principle of least privilege, granting access only to those who genuinely need it. Coupled with other security practices and protocols, such as VPNs, whitelisting IPs and subnets contributes to a comprehensive and multi-layered security posture for your cloud-based applications. For more information on configuring security groups, refer to the official AWS documentation.

Remember that in the realm of cloud security, a proactive approach is the key to preventing potential breaches and ensuring the integrity of your applications.

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