What is Packet Filtering? Key Concepts for Network Security

What if a small change to your network could dramatically increase cybersecurity, strengthen data privacy compliance, and help save on appliance hardware costs?

Packet filtering is a powerful technique that gives you precise control over your network traffic.

Let's explore how packet filtering works, why it matters, and how it can transform your organization's network visibility and security posture.

Understanding Packet Filtering: The Foundation of Network Visibility

To fully understand packet filtering, we need to talk about network TAPs and packet brokers. These tools are used to connect network monitoring, performance and security tools.

Network packet brokers receive live data on network links, make a mirror copy of the data and forward it to one of many appliances, while allowing the live data to continue to its intended destination.

Most networks use several specialized appliances on each link – sometimes seven or more in complex networks. These devices monitor traffic, generate reports, block threats, detect anomalies, and improve performance. However, each appliance only needs specific data relevant to its function, not all network traffic. When you multiply this filtering requirement across multiple links and appliances, it creates a significant management burden.

How Packet Filtering Works

The packet broker receives all data from the live link and, using pre-programmed policies, sends only relevant packets to each connected appliance.

Packet filtering can be implemented in several ways:

• IP-based filtering: only allows packets from pre-approved source and destination addresses

• Application-based filtering: blocks specific traffic types like web or email

• Content masking: forwards complete packets but hides payload contents to maintain data confidentiality

Static vs. Dynamic Packet Filtering

Stateful inspection, also known as dynamic filtering maintains a list of established connections and analyzes the application layer of packets, making it better at detecting fake packets. In contrast, stateless or static filtering only examines packet headers without tracking previous connections. This makes stateless filtering faster but less secure since each packet is processed individually without context.

CapEx Advantages of Packet Filtering

Packet filtering significantly reduces costs associated with deploying multiple traffic management appliances. Rather than connecting numerous appliances directly to each network link, filtering decreases traffic volume to each appliance, freeing up processing capacity. By filtering unnecessary packets and aggregating traffic from underutilized links, you can dramatically reduce the number of appliances you need.

These filtering capabilities also help monitoring and security appliances process traffic more efficiently. With reduced traffic loads, you can purchase appliances with lower processing power and storage requirements, further decreasing your hardware investment.

Filtering with Network Critical: Advanced Network Visibility Solutions

Network Critical is a global leader in network visibility. We offer a robust portfolio of network packet brokers with advanced features at speeds and configurations suitable for a wide variety of networks. In addition to intelligent packet filtering, Network Critical packet brokers include additional advanced features such as : 

• Zero packet loss with total packet capture

• Traffic aggregation from multiple TAP and/or SPAN ports

• Load balancing to multiple appliances

• Single pane management with a Graphical User Interface (GUI) for simplicity and accuracy

• Application layer packet visibility

• Product range covering 1Gbps to 400Gbps scalable to 256 ports

Connecting and managing network appliances with smart packet brokers offer many advantages, including: 

• Increased security

• Accurate and complete packet visibility

• Better network performance

• Compliance with international data protection standards.

Our experts can audit your current infrastructure and recommend architectural improvements that optimize operations while potentially reducing your hardware capital expenditure.

Ready to enhance your network visibility?

Learn how our solutions can strengthen your security posture while optimizing network performance.