Firewall And Filtering

Sample Solution

Introduction Andrew's Biometrics Corp (ABC) is a company that specializes in biometric security solutions. The company has a series of load balanced Web servers that provide information about the organization, advertise products, process online orders, and allow customers to make payments. The company's data infrastructure is constantly being attacked by hackers, and network administrators are being challenged on a daily basis to defend their intranet and other systems on the Internet. Problem Statement ABC needs to protect its load balanced Web servers from denial-of-service attacks. Traditional firewalls are not effective at mitigating these types of attacks, as they typically filter packets based on protocol types or IP addresses. ABC needs a firewall that can filter packets based on content, as well as one that can understand the state of active network connections. Industry Resources

• National Institute for Standards & Technology (NIST): NIST Cybersecurity Framework (CSF)
• Institute of Electrical and Electronic Engineers (IEEE): IEEE Standard for Information Technology - Telecommunications and Information Exchange between Systems - Local and Metropolitan Area Networks - Specific Requirements - Part 3: CSMA/CD Access Method and Physical Layer Specifications
• Internet Engineering Task Force (IETF): RFC 5735 - Network Security with IPsec

Demilitarized Zone (DMZ) A DMZ is a network segment that is located between an organization's internal network and the Internet. The DMZ is typically used to host publicly accessible servers, such as Web servers and email servers. The DMZ helps to protect the organization's internal network from unauthorized access, even if the DMZ servers are compromised. Network Segmentation Network segmentation is the process of dividing a network into smaller subnetworks. This helps to improve security and performance by isolating different types of traffic and preventing unauthorized access to critical systems. Firewall Types

• Packet-filtering firewall: Packet-filtering firewalls filter packets based on source and destination IP addresses, port numbers, and protocols.
• Stateful inspection firewall: Stateful inspection firewalls keep track of active network connections and use this information to make decisions about whether or not to allow traffic.
• Application-layer firewall: Application-layer firewalls inspect the content of packets to determine whether or not to allow traffic.

Design Considerations When designing a network security solution for ABC, the following considerations must be taken into account:

• Security: The solution must be effective at protecting the company's Web servers from denial-of-service attacks and other threats.
• Performance: The solution must not have a significant impact on the performance of the company's network.
• Scalability: The solution must be able to scale to meet the needs of the company as it grows.
• Cost: The solution must be cost-effective.

Recommended Firewall The recommended firewall for ABC is a next-generation firewall (NGFW). NGFWs are a type of application-layer firewall that can inspect the content of packets to determine whether or not to allow traffic. NGFWs are also able to keep track of active network connections and use this information to make decisions about whether or not to allow traffic. Visio Diagram Opens in a new windowlessonsintech.wordpress.com Visio diagram showing the proposed firewall layout Implementation The following steps can be taken to implement the proposed firewall layout:

1. Deploy a NGFW in the DMZ.
2. Configure the NGFW to allow traffic to the Web servers.
3. Configure the NGFW to block all other traffic to the DMZ.
4. Configure the NGFW to inspect the content of packets and block those that contain malicious content.
5. Configure the NGFW to keep track of active network connections and use this information to make decisions about whether or not to allow traffic.

Conclusion The proposed firewall layout will help to protect ABC's Web servers from denial-of-service attacks and other threats. The NGFW will be able to inspect the content of packets and block those that contain malicious content. The NGFW will also be able to keep track of active network connections and use this information to make decisions about whether or not to allow traffic.