I've been working on improving my network security skills, and I'm diving into using Nmap for scanning networks. I understand the basics of running a simple scan to discover active hosts and open ports, but I'm curious about some of the more advanced capabilities of Nmap.
Service and Version Detection: How accurate is Nmap's detection of services and their versions? Are there specific flags I should be aware of that enhance the accuracy of this detection?
Scripted Scans: I've heard that Nmap has the ability to use scripts for more detailed scanning. What are some useful scripts that I should look into for evaluating network security vulnerabilities?
Evading Firewalls: Although it's important to respect privacy and legal boundaries, I'm interested in understanding how Nmap can (legally) be used to test firewall configurations. What are some methods to consider when trying to evaluate firewall rules using Nmap?
Performance Optimization: When scanning large networks, what are some best practices to optimize performance and reduce scan time without compromising the results?
Detecting VPNs and Proxies: Can Nmap be used to detect the presence of VPNs or proxies on a network? If so, what techniques or scripts are most effective for this?
Any insights or resources that the community could share would be greatly appreciated!