Adjusting timing parameters

Nmap not only adjusts itself to different network and target conditions while scanning, but it can be fine-tuned using timing options to improve performance. Nmap automatically calculates packet round trip, timeout, and delay values, but these values can also be set manually through specific settings.

The following recipe describes the timing parameters supported by Nmap.

How to do it...

Enter the following command to adjust the initial round trip timeout, the delay between probes, and a time out for each scanned host:

# nmap -T4 --scan-delay 1s --initial-rtt-timeout 150ms --host-timeout 15m -d scanme.nmap.org 
   --------------- Timing report --------------- 
     hostgroups: min 1, max 100000 
     rtt-timeouts: init 150, min 100, max 1250...