Apologies, but we have had such unsavory characters seek to abuse the Monastery in the past, and your initial request seemed somewhat fishy. You were making a round-about request for a "port scanner", which can have legitimate uses like yours, but is also a well-known cracker tool. Later interactions have cleared up my suspicions.
The command you gave uses netcat to exchange UDP packets (the -u selects UDP) with port 27900 on 333networks.com. I have socat installed, which is a similar, but somewhat more advanced (and complex) program. It is possible there may be some portability issues between our shells or other system weirdness. The Perl version should have solved that problem.