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There’s a lot of network wizardry that goes on behind the scenes every time you load up a webpage. However, while most of the magic helps serve web pages and keep you safe, some network practices that go unnoticed leave you vulnerable to attackers.
Deep Packet Inspection (DPI) isn’t something the average internet user talks about every day (or ever). However, it can massively impact your privacy.
What Is Deep Packet Inspection?
Deep Packet Inspection (DPI), also known as packet sniffing, is a method of examining the contents of data packets when they arrive at a certain checkpoint in a network. It’s akin to airport security patting you down before you get on an airplane, except DPI does this for data packets, ensuring no malicious packets get in or out of the network.
DPI works using specific, predetermined rules from the network admin or an ISP. Not only can it detect malicious or otherwise rule-breaking data packets, but it can also pinpoint the application or service the packet originated from,much like the Traceroute tool. Additionally, DPI can also work with filters, enabling it to identify and reroute network traffic that comes from a specific online service or IP address.
DPI is a very effective tool for protecting your network. Network administrators often use it as an intrusion detection system or even an intrusion prevention system, courtesy of its data packet tracking capabilities. It’s also used by organizations that allow employees to bring their own PCs to work and connect to the company’s servers using a VPN to prevent the accidental spread of spyware, malware, worms, or viruses.
Since it can also work with filters, it allows network administrators to control which applications can send data through their network. Additionally, it can also help handle network traffic better, preferring data packets from high-priority applications over others to ensure seamless communication.
Last but not least, ISPs often use DPI to prevent attackers from sending malicious requests over their networks, protecting more vulnerable devices like Internet of Things capable devices that don’t necessarily have the best security measures in place. It can also help ISPs block DDoS attempts on IoT devices and regulate web content according to the specific region’s data rules.
How Is DPI Different From Conventional Packet Filtering?
Normal packet filtering or inspection techniques only check the information of a data packet’s header, including information like the destination IP address, source IP address, and port number.
DPI, on the other hand, reads a much wider range of metadata in addition to data connected with each packet the device interfaces with. This means that DPI takes a whiff at both the data packet’s header and the actual data it’s carrying. Additionally, DPI can also identify the sender and receiver for individual data packets, including the application they originated from, something that regular packet filtering techniques can’t do.
This makes DPI a far more effective method of network packet filtering. DPI can also find hidden threats within the network’s data stream, flagging any attempts at data extraction, malware intrusion, or violations of the network’s content policies.
How Does DPI Impact Your Internet Privacy?
While DPI was created to protect users from network threats, it does so in quite an invasive way. ISPs or companies often employ this filtering method to block specific websites or content from their networks.
However, when you consider that DPI goes through every data packet leaving your computer, it immediately becomes a privacy nightmare. There have been many documented cases of DPI being used for not-so-good purposes, including governments censoring internet information and in marketing or advertising, where companies can monitor user behavior and sell browsing or other data to marketing or advertising companies.
The primary concern here is that DPI can identify the recipient or sender of a particular data packet. This means that if your network is compromised, or you’re connected to a malicious network that runs DPI on data packets traveling through your entire internet activity can be very easily traced.
That’s yet another reason to stay off public Wi-Fi networks unless you’re in a trusted place. Ourlist of network security tipsis also useful for helping to secure your home network.
How to Protect Yourself From Deep Packet Inspection
The good news is that there are several ways you can protect your precious data packets from DPI’s snooping. While they do require some technical knowledge, most DPI protection tools include extensive documentation and explanations regarding how the tool works. So, if you’ve got a little time on your hands, you can actually protect yourself from DPI fairly well.
DNS Over HTTPS
DNS Over HTTPS or DoH is a security measure built to prevent ISPs from using DPI to surveil their clients and sell that data to marketing, advertising, or any other companies interested in your internet usage data.
With DoH, DNS queries and responses are encrypted before being sent over the HTTP or HTTP/2 protocols. This encryption ensures that attackers can’t forge or otherwise modify DNS traffic—one of the core functionalities DPI enables. Additionally, since DoH hides the name resolution requests, your ISP or anyone eavesdropping on your network can’t see your internet activity.
It’s also easy to use on most popular web browsers, including Chrome, Edge, Firefox, and practically any other Chromium-enabled browser, by enabling the Secure DNS option. You can also enable it on Windows, Linux, or macOS by simply changing the DNS address your computer uses. You should check out ourlist of DNS servers for improved internet securityif you’re looking for options.
However, Secure DNS and other DNS Over HTTPS options only protect DNS requests. They don’t and cannot protect against other forms of Deep Packet Inspection
GoodByeDPI
GoodByeDPI is a free and open-source DPI circumvention utility for Windows. It can work with Windows 7, 8, 8.1, 10, or 11, provided you give it administrative access on your PC. It handles DPI connections using optical splitters or port mirroring, which do not block any data by replying faster than the requested destination.
It blocks both passive and active DPI and should work on most ISPs without any additional configuration. However, if the tool’s default configuration cannot circumvent your ISP’s DPI, theGoodByeDPI GitHub pageprovides helpful instructions on how to work around the issue.
If you’re using Linux or macOS, you may use Spoof-DPI instead. Similar to GoodByeDPI, Spoof-DPI is a simple and lightweight DPI prevention utility that’s open-source and free to use/download.
Depending on whether you’re using Linux or macOS, there are several ways of installing the tool, as detailed on theSpoof-DPI’s GitHub page. Also keep in mind that Spoof-DPI doesn’t bypass DPI for HTTP requests, but still serves a proxy connection for all HTTP requests. It also doesn’t decrypt any HTTPS requests and, hence, doesn’t require any SSL certificates.
