Scanning can be conducted at various speeds. Slower speeds are less likely to be detected by IDS systems, while faster scans may overwhelm the target system. Nmap offers the following timing options:
- T0 – Paranoid: This setting is for attackers who want to remain undetected. It sends very few packets per second to avoid triggering IDS systems that correlate multiple requests within a short timeframe.
- T1 – Sneaky: Faster than T0, but still designed to evade detection by IDS systems.
- T2 – Polite: A slower scan that minimizes the risk of crashing a system.
- T3 – Normal: This is the default scanning speed.
- T4 – Aggressive: A fast scan that yields results quickly, suitable for most systems.
- T5 – Insane: This setting sends packets at maximum capacity and performance.
Zenmap
Nmap includes a built-in GUI (Graphical User Interface) along with other tools. The GUI is helpful for visualizing networks and browsing open ports on various hosts. Here’s what the GUI looks like:
