I have several questions about nmap. First, nmap can detect servers via:link-layernetwork-layertransport-layerWhat are the differences (not in the layer, but in the way that nmap does it) and how does nmap do this?Second, when I port scan with nmap, the UDP scan takes much longer then the TCP scan. Why?Third: are there any different methods to explore the OS then to use the -O --osscan-guess command (I mean totally different, not e.)?
Questions about nmap
networking;nmap