knocker software package provides Simple and easy to use TCP security port scanner, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install knocker
knocker is installed in your system.
Make ensure the knocker package were installed using the commands given below,
$ sudo dpkg-query -l | grep knocker *
You will get with knocker package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Network |
| Package | knocker |
| Version | 0.7.1-4 |
| Description | Simple and easy to use TCP security port scanner |
| Sub Section | Net |