firewalk command not found

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

Introduction

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

firewalk: command not found

or when using sudo you get the following error message

sudo: firewalk: command not found

Solutions to firewalk: command not found

How To Fix firewalk: command not found in Ubuntu / Debian / Kali Linux / Raspbian

In Ubuntu firewalk is provided by firewalk package.

firewalk is:

Firewalk is an active reconnaissance network security tool that attempts to determine what layer 4 protocols a given IP forwarding device will pass. It works by sending out TCP or UDP packets with a TTL one hop greater than the targeted gateway. If the gateway allows the traffic, it will forward the packets to the next hop where they will expire and elicit an ICMP_TIME_EXCEEDED message. Otherwise, it will likely drop the packets and there will be no response.

To get the correct IP TTL that will result in packets expiring one hop beyond the gateway, Firewalk needs to ramp up hop counts. It does this in the same manner that traceroute works. Once the scan is bound (that is, Firewalk knows the gateway hop count), it begins the scan. The ultimate destination host does not have to be reached, it only needs to be somewhere downstream, on the other side of the gateway, from the scanning host.

Firewalk helps in assessing the security configuration of packet filtering devices, such as those used in firewall systems. It is relevant for network security assessments, like network penetration tests (pentests).

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

sudo apt-get -y install firewalk

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

You can also use apt command to install firewalk.

sudo apt -y install firewalk

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

sudo aptitude install firewalk

Summary

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