fastnetmon-rewritten/docs/FreeBSD_INSTALL.md

FreeBSD 9, 10, 11

Install dependencies:

pkg install cmake git ncurses boost-all log4cpp

Update linker paths:

/etc/rc.d/ldconfig restart

mkdir /usr/local/src
cd /usr/local/src
git clone https://github.com/FastVPSEestiOu/fastnetmon.git
cd fastnetmon/src
mkdir build
cd build
cmake ..
make

Or you can try native FreeBSD port (will be added to port tree soon):

pkg install cmake git ncurses boost-all log4cpp
/etc/rc.d/ldconfig restart

mkdir /usr/local/src
cd /usr/local/src
git clone https://github.com/FastVPSEestiOu/fastnetmon.git
cd fastnetmon/src/FreeBSD_port/
make makesum
make install 

For netmap support you may need compile kernel manually with this manual.