Why Use Stateful Packet Inspection?

The Internet is a constantly changing network. This means that on any given day, there are new threats and vulnerabilities to worry about. One of the best ways to protect your company from these is using stateful packet inspection (SPI). 

SPI can be used for deep packet inspection and protocol analysis to understand what packets coming into or going out of your network represent.

How Does The Stateful Packet Inspection System Work?

The first step of SPI is to build a state table. In this table, you will track all the vital information about the traffic that comes into and out of your network each day. This information includes what types of packets have been seen before, how often they have appeared if they seem legitimate or suspicious, and so on. 

The more data points you gather for a given packet over time, the better picture you can get as to whether it should be allowed in or out of your network based on its past behavior patterns

Types Of Stateful Inspection

There are two different kinds of stateful inspection:  Stateful Inspection (also called “deep” or “intelligent”) firewall technology inspects packets at every layer within an OSI model Layers. It can track the protocol being used for a given packet and what state it is in at any given time.

Deep Stateful Inspection 

This is best for businesses that want to be proactive about dealing with threats and vulnerabilities by using SPI. It makes it possible to allow or block packets based on what your company is trying to accomplish at the moment, rather than just looking at where they are coming from.

Intelligent Stateful Inspection

Intelligent Stateful Inspection is much more complicated to set up. Still, it is also one of the most secure ways to protect your company from threats coming in via packet inspection.

What Are Some Benefits Of Using SPI?

There are many reasons why you should use SPI for deep packet inspection and protocol analysis. The most important benefit is that SPI can help keep your network secure and safe from new Internet threats. SPI can also help prevent attackers from gaining access to your network and causing problems.

There are many other reasons why you should use SPI for deep packet inspections and protocol analysis, including: 

  • You don’t have to make any changes to your network infrastructure for SPI to work. 
  • You can use it on existing equipment, so there is no need to buy new hardware or software. 
  • It uses a high-performance inspection engine and a state table lookup mechanism.

Who Should Use Stateful Packet Inspection?

Any organization that is concerned about Internet threats will benefit from using SPI today. Since the system operates at layer two, it requires minimal configuration or reconfiguration for you to start inspecting packets with it right away. This means that the time it takes to get started is minimal, making SPI an excellent solution for almost every organization.

The prominent organizations that will benefit from using SPI are:

  • Network security professionals need to stay up-to-date with new threats and vulnerabilities. 
  • ISPs, carriers, WISPs, or telecommunications companies that want their customers to have the best possible experience online each day.

Networks of all sizes can use SPI for deep packet inspection and protocol analysis. This includes small businesses, nonprofits, and everything in between.

What Are Some Considerations For Implementing SPI?

Things To Consider When Planning Your Network’s Implementation

There are only a few things to consider when planning your network’s implementation of SPI. The first is that if there isn’t enough memory on your router, the inspection process will take longer. This means that it is essential to have enough memory before getting started with deep packet inspections and protocol analysis for SPI to work correctly.

Things You Can Do To Improve Your Network’s SPI Implementation

There are many things you can do to improve how effective your network’s SPI implementation is. The first is to ensure that your network has enough resources for the SPI process since it requires a lot of memory on your router or switch. You also need to have access to an analysis engine so you can use the information gathered by SPI’s deep packet inspections and protocol analyses.

Things You Should Avoid When Inspecting Packets

You should avoid a few things when using SPI to inspect packets coming into or going out of your network. The first is that it isn’t effective at inspecting encrypted traffic, so if this type of information makes up part of your business’s communication process, you may not be able to use SPI as intended. You also shouldn’t use SPI to look for IP options.


Packet inspection is necessary to protect network infrastructures from Internet threats. SPI firewall technology uses deep packet inspections and protocol analysis to help your company avoid problems with malware, intruders, spam emails, etc.

Recent Posts