nDPI

nDPI

What is nDPI ?

nDPI® is an open source library for deep-packet inspection. Some dissectors (e.g. TLS and DNS) are released under a dual-license while the rest of the library is LGPLv3: please refer to README.license.md for more information.

A generic FAQ about nDPI is available here

How To Compile nDPI

In order to compile this project do

• ./autogen.sh && ./configure
• make

If you get some errors while compiling croaring.c, try:

• ./autogen.sh && ./configure --enable-old-croaring
• make

To compile the library w/o any tools or tests:

• ./autogen.sh && ./configure --with-only-libndpi
• make

Out-of-tree builds are supported:

• ./autogen.sh
• mkdir build
• cd build
• …/configure && make

To run tests do additionally:

• ./tests/do.sh # Generate and check for diff’s in PCAP files
• ./tests/do-unit.sh # Run unit tests
• ./tests/do-dga.sh # Run DGA detection test

or run all with: make check

Please note that the (minimal) pre-requisites for compilation include:

• GNU tools (autoconf automake libtool pkg-config gettext flex bison)
• GNU C compiler (gcc) or Clang

On Debian/Ubuntu systems do:

• sudo apt-get install build-essential git gettext flex bison libtool autoconf automake pkg-config libpcap-dev libjson-c-dev libnuma-dev libpcre2-dev libmaxminddb-dev librrd-dev

On RockyLinux (and other RHEL-based) systems do:

• sudo dnf install epel-release dnf-plugins-core
• sudo dnf config-manager --set-enabled crb
• sudo dnf install gcc make git gettext flex bison libtool autoconf automake pkgconf-pkg-config libpcap-devel json-c-devel numactl-devel pcre2-devel libmaxminddb-devel rrdtool-devel

On Arch Linux:

• sudo pacman -S gcc git gettext flex bison libtool autoconf automake pkg-config libpcap json-c numactl pcre2 libmaxminddb rrdtool

On FreeBSD:

• sudo pkg install gcc git gettext flex bison libtool autoconf automake devel/pkgconf gmake libpcap json-c pcre2 libmaxminddb rrdtool

Remember to use gmake and not make on FreeBSD

On MacOS:

• brew install coreutils gcc git gettext flex bison libtool autoconf automake pkg-config libpcap json-c pcre2 libmaxminddb rrdtool

On Windows:

There are three supported ways to build nDPI:

1. MSYS2 (assuming MSYS2 already installed):

• msys2 -c “pacman --noconfirm -S --needed --overwrite ‘*’ git mingw-w64-x86_64-toolchain automake1.16 automake-wrapper autoconf libtool make mingw-w64-x86_64-json-c mingw-w64-x86_64-crt-git mingw-w64-x86_64-pcre2 mingw-w64-x86_64-libpcap”

2. Mingw-w64

3. Visual Studio (see windows/nDPI.sln)

Note: All Windows versions require npcap with WinPcap compatibility mode enabled.

How To Build The Documentation

• pip install --upgrade pip
• pip install -r doc/requirements.txt
• make doc

Use the builtin python3 webserver to view documentation:

• make doc-view

How To Add A New Protocol Dissector

The entire procedure of adding new protocols in detail:

1. Add new protocol together with its unique ID to: src/include/ndpi_protocol_ids.h
2. Create a new protocol in: src/lib/protocols/
3. Variables to be kept for the duration of the entire flow (as state variables) need to be placed in: src/include/ndpi_typedefs.h in ndpi_flow_tcp_struct (for TCP only), ndpi_flow_udp_struct (for UDP only), or ndpi_flow_struct (for both).
4. Add a new entry for the search function for the new protocol in: src/include/ndpi_private.h
5. Choose (do not change anything) a selection bitmask from: src/include/ndpi_define.h
6. Set protocol default ports in ndpi_init_protocol_defaults in: src/lib/ndpi_main.c
7. Be sure to have nBPF support, cloning PF_RING in the same directory where you cloned nDPI: git clone https://github.com/ntop/PF_RING/ && cd PF_RING/userland/nbpf && ./configure && make. You can ignore the /bin/sh: 1: ../lib/pfring_config: not found error
8. From the nDPI root directory, ./autogen.sh && ./configure --with-pcre2 (nBPF and PCRE2 are usually optional, but they are needed to run/update all the unit tests)
9. make
10. make check
11. Update the documentation, adding this new protocol to doc/protocols.rst
12. Update the Windows Visual Studio configuration, adding the new c file in windows/nDPI.vcxproj

How to use nDPI to Block Selected Traffic

You can use nDPI to selectively block selected Internet traffic by embedding it onto an application (remember that nDPI is just a library). Both ntopng and nProbe cento can do this.

nDPI Paper Citation

• Deri, Luca, et al. nDPI: Open-source high-speed deep packet inspection 2014 International Wireless Communications and Mobile Computing Conference (IWCMC). IEEE, 2014.

Videos and Presentations

• The Ultimate Guide to nDPI [2025]
• Using nDPI to solve real life problems: from First Packet Classification to Obfuscated Traffic detection [PacketFest, 2025]
• Passive Network Traffic Fingerprinting [FOSDEM, 2025]
• A Deep Dive Into Traffic Fingerprints using Wireshark [SharkFest, 2024]
• Network Traffic Classification for Cybersecurity and Monitoring [FOSDEM, 2022]
• Using nDPI for Monitoring and Security [FOSDEM, 2021]
• Knowing the Unknown: How to Monitor and Troubleshoot an Unfamiliar Network [SharkFest, 2017]

nDPI-Related Projects

• nfstream
• nDPId

DISCLAIMER

While we do our best to detect network protocols, we cannot guarantee that our software is error free and 100% accurate in protocol detection. Please make sure that you respect the privacy of users and you have proper authorization to listen, capture and inspect network traffic.

nDPI is a registered trademark in the US and EU.