Test for open TCP/UDP Ports

Hello List,

i would like to test if i can reach an open TCP and UDP Port.

Here is the way i use to test a tcp port (-sT does a full handshake,
right?!):
   /usr/bin/nmap -sT --data-length 10 -n -q -r -e eth0:0 -P0 --open -T
Aggressive -p 1234 123.123.123.123
The results seem to make sense here.

This is the way how i check a UDP Port:
   /usr/bin/nmap -sU --data-length 10 -n -q -r -e eth0:0 -P0 --open -T
Aggressive -p 1234 123.123.123.123

the weird thing is that it still reports an open port if i unplug the
network cable of 123.123.123.

Where can i read up how nmap does its udp scan?

Thanks, Mario

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Received on Apr 02 2008