Building fox3

Prerequisites

The SQLite driver (mattn/go-sqlite3) is a CGO package — a C compiler is required on every platform. The binary will not build without one.

Windows

Install Go and TDM-GCC (or any MinGW-w64 distribution). Ensure both are on PATH.

git clone https://github.com/nzyuko/fox3
cd fox3

# Build
go build -o fox3_server.exe .

# Verify all packages compile
go build ./...

# Static analysis (known non-fatal warnings — see docs/architecture.md)
go vet ./...

# Run
.\fox3_server.exe --password <strong-password>

Stamp a release build

$commit = git rev-parse --short HEAD
go build -ldflags "-X github.com/nzyuko/fox3/v2/pkg.Build=$commit" -o fox3_server.exe .

Linux

Install Go and GCC via your package manager, then build natively. Do not cross-compile from Windows for a production Linux binary — the CGO cross-toolchain setup is non-trivial and not documented here.

Debian / Ubuntu

sudo apt update
sudo apt install -y golang gcc git

git clone https://github.com/nzyuko/fox3
cd fox3

CGO_ENABLED=1 go build -o fox3_server .
./fox3_server --password <strong-password>

Fedora / RHEL

sudo dnf install -y golang gcc git

git clone https://github.com/nzyuko/fox3
cd fox3

CGO_ENABLED=1 go build -o fox3_server .
./fox3_server --password <strong-password>

Arch Linux

sudo pacman -S go gcc git

git clone https://github.com/nzyuko/fox3
cd fox3

go build -o fox3_server .
./fox3_server --password <strong-password>

Notes

• The Go toolchain sets CGO_ENABLED=1 by default when building natively, so the explicit flag is optional but recommended for clarity.
• The server binary has no runtime dependency on GCC — GCC is only needed at compile time.
• The SQLite database is created at data/fox3.db relative to the working directory where you run the server, not the binary location.

Systemd unit (optional)

[Unit]
Description=fox3 C2 server
After=network.target

[Service]
Type=simple
WorkingDirectory=/opt/fox3
ExecStart=/opt/fox3/fox3_server --password <strong-password> --rest 0.0.0.0:8080
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target

sudo cp fox3.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now fox3

macOS

Install Go via go.dev or Homebrew. Xcode Command Line Tools provides the C compiler.

xcode-select --install
brew install go  # or download from go.dev

git clone https://github.com/nzyuko/fox3
cd fox3
go build -o fox3_server .
./fox3_server --password <strong-password>

Rebuilding the frontend

The compiled React assets are committed to frontend/dist/ and served directly by the REST server. You only need to rebuild if you edit frontend/src/.

cd frontend
npm install
npm run build
# Output lands in frontend/dist/ — commit the result

The server resolves frontend/dist/ relative to the working directory at startup. If the directory is not found there, it falls back to <executable-dir>/frontend/dist/.

Known build warnings (go vet)

These are pre-existing issues inherited from the Merlin codebase and are non-blocking:

The DNS/DoH vet warnings are only relevant once those listener types are wired into the factory.