Fast Scan: Scan fewer ports than the default scan (a few seconds)
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Default Scan: By default, Nmap scans the top 1,000 ports for each scan protocol requested. This catches roughly 93% of the TCP ports and 49% of the UDP ports. (about 5 sconds)
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Detailed Scan: Default scan with enabled OS detection, version detection, script scanning and traceroute (up to 30 seconds and more)