How To Install fwknop-server on Debian 11

In this tutorial we learn how to install fwknop-server on Debian 11. fwknop-server is FireWall KNock OPerator server side - C version

Introduction

In this tutorial we learn how to install fwknop-server on Debian 11.

What is fwknop-server

fwknop-server is:

The FireWall KNock OPerator implements an authorization scheme called Single Packet Authorization (SPA), based on Netfilter and libpcap.

Its main application is to protect services such as OpenSSH with an additional layer of security in order to make the exploitation of vulnerabilities (both 0-day and unpatched code) much more difficult.

The authorization server passively listens for authorization packets via libpcap, thus preventing any connections from being processed on the traditional port. Access to a protected service is only granted after a valid encrypted and non-replayed packet is detected.

There are three methods to install fwknop-server on Debian 11. We can use apt-get, apt and aptitude. In the following sections we will describe each method. You can choose one of them.

Install fwknop-server Using apt-get

Update apt database with apt-get using the following command.

sudo apt-get update

After updating apt database, We can install fwknop-server using apt-get by running the following command:

sudo apt-get -y install fwknop-server

Install fwknop-server Using apt

Update apt database with apt using the following command.

sudo apt update

After updating apt database, We can install fwknop-server using apt by running the following command:

sudo apt -y install fwknop-server

Install fwknop-server Using aptitude

If you want to follow this method, you might need to install aptitude first since aptitude is usually not installed by default on Debian. Update apt database with aptitude using the following command.

sudo aptitude update

After updating apt database, We can install fwknop-server using aptitude by running the following command:

sudo aptitude -y install fwknop-server

How To Uninstall fwknop-server on Debian 11

To uninstall only the fwknop-server package we can use the following command:

sudo apt-get remove fwknop-server

Uninstall fwknop-server And Its Dependencies

To uninstall fwknop-server and its dependencies that are no longer needed by Debian 11, we can use the command below:

sudo apt-get -y autoremove fwknop-server

Remove fwknop-server Configurations and Data

To remove fwknop-server configuration and data from Debian 11 we can use the following command:

sudo apt-get -y purge fwknop-server

Remove fwknop-server configuration, data, and all of its dependencies

We can use the following command to remove fwknop-server configurations, data and all of its dependencies, we can use the following command:

sudo apt-get -y autoremove --purge fwknop-server

Dependencies

fwknop-server have the following dependencies:

References

Summary

In this tutorial we learn how to install fwknop-server package on Debian 11 using different package management tools: apt, apt-get and aptitude.