We pre-compile FTLDNS for you to save you the trouble of compiling anything yourself. However, sometimes you may want to make your own modifications. To test them, you have to compile FTLDNS from source. Luckily, you don't have to be a programmer to build FTLDNS from source and install it on your system; you only have to know the basics we provide in here. With just a few commands, you can build FTLDNS from source like a pro.

Install native build environment

This will install all necessary tools to build FTL directly in your host operating system. It is usually the easiest solution and works with all editors available.

Installing the Required Software

First, we'll install the basic software you'll need to compile from source, like the GCC compiler and other utilities. Install them by running the following command in a terminal:

Debian / Ubuntu / Raspbian

sudo apt install git wget ca-certificates build-essential libgmp-dev m4 cmake libidn2-dev libunistring-dev libreadline-dev xxd

Fedora

sudo dnf install git wget ca-certificates gcc gmp-devel gmp-static m4 cmake libidn2-devel libunistring-devel readline-devel xxd

Compile libnettle from source

FTLDNS uses a cryptographic library (libnettle) for handling DNSSEC signatures. Compile and install a recent version using:

wget https://ftp.gnu.org/gnu/nettle/nettle-3.9.1.tar.gz
tar -xzf nettle-3.9.1.tar.gz
cd nettle-3.9.1
./configure --libdir=/usr/local/lib --enable-static --disable-shared --disable-openssl --disable-mini-gmp -disable-gcov --disable-documentation
make -j $(nproc)
sudo make install

Since Ubuntu 20.04, you need to specify the library directory explicitly. Otherwise, the library will be installed in custom locations where it would not be found by cmake.

Compile libmbedtls from source

FTLDNS uses another cryptographic library (libmbedtls) containing cryptographic primitives, X.509 certificate manipulation and the SSL/TLS and DTLS protocols used for serving the web interface and the API over HTTPS.

Compile and install a recent version using:

wget https://github.com/Mbed-TLS/mbedtls/archive/refs/tags/v3.5.0.tar.gz -O mbedtls-3.5.0.tar.gz
tar -xzf mbedtls-3.5.0.tar.gz
cd mbedtls-3.5.0
sed -i '/#define MBEDTLS_THREADING_C/s*^//**g' include/mbedtls/mbedtls_config.h
sed -i '/#define MBEDTLS_THREADING_PTHREAD/s*^//**g' include/mbedtls/mbedtls_config.h
make -j $(nproc)
sudo make install

The sed commands are necessary to enable multi-threading support in libmbedtls as there is no configure script to do this for us (see also here).

Get the source

Now, clone the FTLDNS repo (or your own fork) to get the source code of FTLDNS:

git clone https://github.com/pi-hole/FTL.git && cd FTL

If you want to build another branch and not master, use checkout to get to this branch, like

git checkout development-v6

Compile the source

FTLDNS can now be compiled using either the build script

./build.sh

or manually

mkdir -p cmake && cd cmake
cmake ..
cmake --build . -- -j $(nproc)

Note that both ways are exactly equivalent and that you do not need root privileges here.

Install the new binary system-wide

Install the new binary using either

./build.sh install

or

cd cmake && sudo make install

Finally, restart FTLDNS to use the new binary:

sudo service pihole-FTL restart

Caution

Once your homebrew pihole-FTL binary is built and installed, do not run pihole -up or pihole checkout. These commands might overwrite your local pihole-FTL binary with Pi-hole's pre-compiled binaries.

Use containerized build environment

While most people think of Docker as a deployment environment, it's also a wonderful tool to create and maintain build environments. Pi-hole provides ftl-build containers composed of everything needed to build FTL for various architectures on your x86_64 hosts. Check out Docker Hub pi-hole/ftl-build for the available build containers as well as the Releases overview for a detailed changelog.

The ftl-build containers can, for instance, easily be used as devcontainers with Visual Studio Code's remote-containers extension. The necessary devcontainer.json is provided in the FTL repository. See the description of the extension for further details. Note that ./build.sh install would only install FTL in the container in this case. Instead, you have to copy the FTL binary generated inside the container yourself to the final destination on your installation target.