What Is Deep Packet Inspection and How Does It Work?
Also known as DPI, deep packet inspection is a kind of packet filtering that evaluates the data and header of a packet that is transmitted through an inspection unit to weed out any control that is non-compliant; any viruses, spam, or intrusions; and any other defined criteria in order to block that packet from passing through the inspection point.
Deep packet inspection can also be used to redirect a packet to another destination. In other words, deep packet inspection can be used to detect, locate, categorize, reroute, or block any packets that have specific data payloads or code that was not done by conventional packet filtering. This goes beyond examining packet headers.
How Does Deep Packet Inspection Work?
Deep packet inspection is a filter for packets that is applied to Open Systems Interconnection’s application layer. It evaluates the content of a packet that goes through a specific checkpoint. It then uses the rules set up either by the organization, the service provider, or the systems administrator in order to determine what to do with the specific packet in real time.
Unlike other packet inspections that only check the header, deep packet inspection can check the contents of the packet and figure out where it came from. It can then determine what to do with it based on this information.
Deep packet inspection can also work with other applications to redirect network traffic.
Deep Packet Inspection Use Cases
Deep packet inspection can be useful in many ways. It can be used as an intrusion detection layer to help identify attacks that were able to get through the firewall.
For organizations that use laptops, deep packet inspection is an important layer for security in order to block malicious programs from entering the network. It can detect if the laptops are being used for prohibited applications.
Another great use of deep packet inspection for organizations is to identify and prioritize data coming through the network. There can be instances where there is a high volume of traffic within a network. Using DPI, it can identify high-priority messages or data, which will be passed on immediately. This feature is also useful for blocking malicious requests.
And of course, deep packet inspection can be used to prevent data leaks as well, such as from outgoing mail. It can inspect not only data coming into the network but also those leaving. By using particular rules, administrators can stop sensitive data from being transmitted out of the network.
Deep Packet Inspection Techniques
There are several techniques that an organization can use regarding deep packet inspection. These include:
- Pattern and signature matching. It can analyze a packet using a database of known network attacks.
- IPS Solutions. They can block detected attacks and unwanted data.
- Protocol anomalies. Default deny can be used, where protocol definitions determine which content should be allowed through.
Challenges With Deep Packet Inspection
No technology is perfect. Although deep packet inspection has many benefits, it also carries a few challenges.
For one, while it can detect and prevent denial-of-service attacks and other similar situations, it can actually be used to carry out the same types of attacks as well.
Depending on the circumstances, deep packet inspection can actually make maintaining firewalls and other security layers of the network a bit more complicated due to the need to continuously revise and update policies for efficient use.
And since deep packet inspection dedicates resources to the firewall, it can slow down the entire network.