Pentesting, also known as penetration testing, is a simulated cyber attack on a computer system, network, or web application to evaluate its security. The main goal of pentesting is to identify vulnerabilities and weaknesses in the target system, so that they can be addressed and secured before a real attack occurs.

There are two main types of pentesting: external network pentesting and internal network pentesting.

External network pentesting simulates an attack from the internet. This type of pentest focuses on the external facing components of the target system, such as firewalls, web applications, and internet-connected devices. The objective of an external network pentest is to identify vulnerabilities that can be exploited by an attacker who is outside the target network.

Internal network pentesting simulates an attack from within the target network. This type of pentest focuses on the internal components of the target system, such as servers, workstations, and internal networks. The objective of an internal network pentest is to identify vulnerabilities that can be exploited by an attacker who has already gained access to the target network.

In conclusion, both external network pentesting and internal network pentesting play a critical role in securing computer systems and networks. Organizations should conduct both types of pentests regularly to identify and address potential vulnerabilities and improve their overall security posture.