Traditional packet filtering may have been sufficient back in the 80s and 90s, but not in today’s world. When it comes to the types of cyber threats businesses face now, deep packet inspection software (DPI) and stateful packet inspection (SPI) are hot topics.
As you might expect, they come with some unique differences. Understanding the roles they play is a crucial part of choosing the right firewalls, analyzing business demands, and navigating your network security architecture.
If you want to avoid feeling overwhelmed by network visibility and analysis, you’ll want to consider the importance of DPI and SPI. This article compares the two for a straightforward answer on how they differ and why both are important in today’s network security landscape.
The Important Role of Packet Inspection
You need network visibility that goes beyond simple port and IP filtering. Where packet inspection comes in is the focus on enabling detection of much more sophisticated threats. This is simply the current state of potential network security threats, hence why DPI and SPI are so common nowadays.
They’re also an important component of granular security policies and support much more control over network traffic as a whole. It’s only becoming more important as time goes on, as it plays a role in many network security demands like troubleshooting, compliance enforcement, and visibility in more dynamic network setups.
What is Deep Packet Inspection?
Considering how technical security appliances can be, it can be easy to let certain specs and features slip through the cracks. DPI works on full packet contents and operates at the application layer for much deeper visibility. Surface-level inspection doesn’t cut it anymore, making DPI a necessity in your network security.
Here are a few other details about DPI that you should know:
- Packet inspection goes through multiple stages like header review, payload decoding, threat signature comparison, and more.
- Techniques specific to DPI include behavior analysis, pattern matching, protocol validation, and statistical anomaly detection.
- Identifies malicious content that can be hidden amongst normal-looking network traffic.
While this might seem like more than enough alongside your hardware and software solutions, you can’t forget about SPI’s role here.
What is Stateful Packet Inspection?
The main difference with SPI is that it focuses on the context of network traffic. What this means is that it makes sure that each packet is a part of a valid, existing session. Much better than what stateless filtering can provide, and it does well to protect your network against connection-related attacks.
Below are several key characteristics unique to stateful packet inspection:
- Defends against certain attacks like session hijacking and TCP spoofing
- Classifies traffic into different states to detect potentially malicious activity
- Uses a ‘state table’ to log important details about network traffic like port numbers, IP addresses, session timing, and more
Although it’s true that SPI is a bit less thorough than the likes of DPI, it’s known to be more efficient with actions like managing connection-level security. Without this breakdown between the two, it can be challenging for new and growing businesses to understand their importance.
Transparency in DPI vs SPI
Between features, capability, and overall integration into your network security, the topic of DPI vs SPI can be rather confusing. That isn’t to say the details don’t matter, but there’s definitely an easier way to digest the information. Check out the table below for a straightforward comparison between DPI and SPI.
| Specification | Barracuda F80 | Barracuda F180 |
|---|---|---|
| Firewall Throughput (Gbps) | 2 | 1.7 |
| VPN Throughput (Mbps) | 720 | 300 |
| IPS Throughput (Mbps) | 600 | 500 |
| NGFW Throughput (Mbps) | 400 | 550 |
| Threat Protection Throughput (Mbps) | 380 | 480 |
| Concurrent Sessions | 80,000 | 100,000 |
| New Sessions per Second | 12,000 | 9,000 |
| Copper Ethernet NICs (GbE) | 5x1 | 6x1 |
It isn’t really about which one you should go for, but why both DPI and SPI are important in today’s cybersecurity landscape. Thankfully, a lot of this is covered in network security hardware, licensing, and even managed services.
Let’s Wrap Up
There’s a lot of technical jargon involved with firewalls and network security, but overlooking this can leave your business wide open to an attack. When you consider the scale of cybersecurity threats that are out there, it’s best to stay ahead of the curve.
For many young and growing companies, this is easier said than done as they go through the necessary learning curve. It never hurts to get a little help along the way, which is where our team members can chime in to assist. We’re always available for a chat if you’d like to learn more about DPI vs SPI and the hardware that can support your network security demands.
