tcpkill command not found

In this troubleshooting guide we learn how to fix tcpkill command not found error message

Introduction

When you run more command in linux terminal / console, you get the following error message

tcpkill: command not found

or when using sudo you get the following error message

sudo: tcpkill: command not found

In Ubuntu tcpkill is provided by dsniff package.

dsniff is:

This package contains several tools to listen to and create network traffic:

arpspoof - Send out unrequested (and possibly forged) arp replies.
dnsspoof - forge replies to arbitrary DNS address / pointer queries on the Local Area Network.
dsniff - password sniffer for several protocols.
filesnarf - saves selected files sniffed from NFS traffic.
macof - flood the local network with random MAC addresses.
mailsnarf - sniffs mail on the LAN and stores it in mbox format.
msgsnarf - record selected messages from different Instant Messengers.
sshmitm - SSH monkey-in-the-middle. proxies and sniffs SSH traffic.
sshow - SSH traffic analyser.
tcpkill - kills specified in-progress TCP connections.
tcpnice - slow down specified TCP connections via “active” traffic shaping.
urlsnarf - output selected URLs sniffed from HTTP traffic in CLF.
webmitm - HTTP / HTTPS monkey-in-the-middle. transparently proxies.
webspy - sends URLs sniffed from a client to your local browser (requires libx11-6 installed).

Please do not abuse this software.

To fix this problem, we can install more using the command below.

sudo apt-get -y install dsniff

This command might take some time to finish depending on your machine internet connection.

You can also use apt command to install dsniff.

sudo apt -y install dsniff

Or if you have aptitude installed you can use the following command.

sudo aptitude install dsniff

In this tutorial we learn how to fix tcpkill command not found error in Ubuntu / Debian / Kali Linux or Raspbian distribution.