Packet crafting is the process of manually creating or editing the existing data packets on a network to test network devices. Hackers and network admins use this process to test a network, check firewall rules, find entry points and test network device’s behaviors.

Network data packets contain various information include data, source address, destination address, version, length, protocol, and few other things depending on the protocol. In packet crafting, one creates a completely new packet or edits the existing packet to change the information packet contains. Then, this packet is sent to the network to see the response of network firewall. By changing values in packet, attackers try to find the entry point in the network to intrude.

I also want to point out that “packet crafting” and “packet spoofing” are not the same thing.

Packet crafting is not a simple task for beginners. It consists of following steps:

Packet Assembly: Creating a new network packet or capture a packet going over the wire and edit the information as per requirement.
Packet Editing: Editing the content of an existing packet
Packet Re/Play: Send/Resend a packet in a network
Packet decoding: Decode and analyze the content of the packet
Tools for all these different steps are available. In this post, I will write about tools used in these steps. Few tools are step-specific while few can be used for performing all steps. You can try few or all the given tools to see how these tools work.

I will also recommend you to read our existing article on Packet Crafting. In that article, we have explained packet crafting in detail with explanation of all four steps involved. We have also shown how to use a few packet crafting tools. That article will help you to understand the packet crafting the usage of those tools. Once you understand clearly, you can read this article to see the available packet crafting tools. Some tools are very old but still work fine. Other tools are actively in development, while still others are no longer in development.

I will also recommend you to learn about network packets, packet structure of different protocols and network layers. If you do not know these things, you will not be able to understand how to do packet crafting and how the things work with these tools. For learning purposes, you must understand the basics of networking before proceeding with the list of these tools. You must know about data packets of different protocols, different fields in packets, the meaning or purpose of those packet fields, and how those packets are used in the network communication. Once you know about those things, you will be able to change those values to see desired effect in the network. So, do not try these tools without learning the previously-mentioned skills. You will end up wasting your time and effort.

These are the 15 best but free packet crafting tools.