Testing the security system using custom packet crafting 

In this section, we will see some special types of scans. In chapter 2, Scanning Pentesting, you saw the port scanner, which works based on the TCP connect scan. A three-way handshake is the underlying concept of the TCP connect scan. 

A half-open scan

The half-open scan or stealth scan, as the name suggests, is a special type of scanning. Stealth-scanning techniques are used to bypass firewall rules and avoid being detected by logging systems. However, it is a special type of scan that is done by using packet crafting, which was explained earlier in the chapter. If you want to make an IP or TCP packet, then you have to mention each section. I know this is very painful and you will be thinking about Hping. However, Python's library will make it simple.

Now, let's take a look at using scapy. Scapy is a third-party library that allows you to make custom-made packets. We will write a simple and short code so that you can understand scapy...