a937eb3b_VulnerabilityAssessment_co_uk__2
[1] known [2] 
Known Port Scanning uses IANA's list of TCP port numbers, as well as any other port numbers observed by Fyodor of the nmap project, to select 1150 ports from the 65K possible to scan. This is equivalent to the nmap "fast scan" option.
VulnerabilityAssessment.co.uk
2