On Debian, the tcpdump program can be found in the dsniff package so install it using:
sudo apt-get dsniff
Example usage:
tcpkill port 80
tcpkill host 184.169.183.106
tcpkill host 184.169.183.106 or 50.18.47.86
The tool does not drop the TCP connection open but drops packets to or from the listed hosts. Any disconnects will come from your client code or the OS after the allowed period of inactivity.