To install it you can then run sudo apt install netcat-traditional or via compiling from source which you can get from the project page. It is no longer maintained and is on version 1.10.īy running apt search netcat on an ubuntu/debian based machine, it appears as netcat or netcat-traditional. This does not typically come preinstalled unless you are using a distro like kali linux.

Netcat traditional is the original implementation and was written by a guy known as Hobbit. You can also find netcat ports for windows that support similar commands to what we’ll look at. Netcat having being initially written for Unix, the variants we will look at are linux based. There are several variants of netcat but most of the core functionality and command line options are very similar. If you would like to test out these commands in a lab environment without the need to install them on your own machine have a look at my scenario on CYBERRANGES using the link below. In this article we’ll look at different applications of netcat and how it can be useful in day to day activities of a pentester, security professional, sysadmin etc… Netcat has been referred to as the TCP/IP / networking swiss army knife. I will leave that for another blog post.Īnd if you want to validate that netcat is indeed listening on that port, you can connect to that port from another workstation by using nmap.Netcat is a tool that reads and writes data across network connections, using TCP or UDP protocol. Have to dig deeper and see what it really means though. The -L means “listen harder, re-listen on socket close” :). If you run this on a Windows 7 machine, you will get this dreaded message “local listen fuxored: INVAL”. The command to have netcat listen on a specific port is “nc -l PORT_NUMBER”. You can download the windows port of the tool at If I am not mistaken, nc comes as a default tool in most of the Linux distros. You can run netcat on your workstation to listen on port 80, assign the IP address of the web server to your workstation and test the rule. But your web server is not built yet and you want to validate the rule. For example, say, you configured your firewall to allow TCP 80 traffic to your web server. You can use it to listen on certain ports or connect to certain ports. Netcat is a swiss army tool for network/security professionals.

Netcat windows command prompt