Re: nmap udp scan time

[visitnikhil () gmail com]

Hello Kevin,

I wish to say something about UDP scan.

In UDP scanning, Open port is detected with no response and a Closed port is detected with ICMP PORT UNREACHABLE (Code 
3, Type 3) response.

Linux kernels limit ICMP error message rates, with Port Unreachable set to 80 per 4 seconds, thereafter implementing a 
1/4 second penalty if the count is exceeded. This makes the scan slow !!

---
Nikhil Wagholikar
Information Security Analyst
NII Consulting
Web: http://wwww.niiconsulting.com

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