For most people, following the basic rules of Internet security, using unique and secure passwords, keeping the system up-to-date, using a firewall, avoiding clicking on things you are not sure of, will be a reasonable defense against hackers. and the malware. But sometimes preventive medicine is not good enough and you need more specialized tools to treat your infection.
Maintaining the network is a fundamental part of progress as a hacker. Intrusions can come at any time, and in many ways, making the defense against you a constant challenge.
These programs are basically modified sniffers that monitor all network traffic.
They detect and alert of any potentially harmful movement.
It is also possible to block the threats by setting the IDS together with the Firewall.
There are also third-party tools to show reports in real time.
The main way to achieve this is to examine the incoming traffic and try to compare it with a database of known harmful activities called signatures.