Ports scanning in reverse when using -r

[Richard van den Berg <richard.vandenberg () ins com>]

I am running nmap 4.11 using the -r (scan ports consecutively) switch.
This makes nmap scan low port numbers first most of the time, but
sometimes I see the port numbers for the same target host counting
backwards. At first I used tcpdump to keep track of the exact progress,
but -d2 shows the same. With -sS -p- I watched (for the same target
host) the ports go from 11000 down to about 7000, then up from 1 to
7000. Very strange to see. At this moment I am watching a simple -sU
count down from 400 to 1. In both cases I am scanning a /24 with 135
active hosts.

Is this intended behavior?

Sincerely,

-- 
Richard van den Berg
Consultant, INS

E-mail: richard.vandenberg () ins com
Mobile: +31 (0)6-52071109

PGP Key ID: 0x6614D2AC
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