Port Scanning with Languard and nmap question

[Carl Wilson <chwilson0607 () yahoo com>]

I scan network devices (such as network
copier/scanners) for open ports and services running
before allowing our users to permanently hook them to
the network. I use nmap 3.70 and Languard. My question
is why do I see different results when both are
configured to look for the same range of ports? (TCP
and UDP) Primarily, the UDP scan of the device returns
ports 53 (DNS), 69 (TFTP), 177 (xdmcp), and 445 (SMB).
Most all the time, Languard does not detect 53, 69,
and 177. 

We had the local user run the scan directly connected
to the device and their results did not find 53, 69,
or 177 open. Any ideas why? Is there something in
scanning across a WAN which would cause these ports to
show as open? Thanks.

Carl

=====
Carl H. Wilson


                
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