Nmap: Network Exploration and Security Auditing Cookbook - Second Edition

How it works...

The command shown previously tells Nmap to scan and report by grouping no less than 100 (--min-hostgroup 100) and no more than 500 hosts (--max-hostgroup 500). It also tells Nmap to retry only twice before giving up on any port (--max-retries 2):

# nmap --min-hostgroup 100 --max-hostgroup 500 --max-retries 2 <target>  

It is important to note that setting these values incorrectly will most likely hurt the performance or accuracy rather than improve it. Nmap sends many probes during its port scanning phase due to the ambiguity of what a lack of response means; either the packet got lost, the service is filtered, or the service is not open. By default, Nmap adjusts the number of retries based on the network conditions, but you ...