Strange behaviour of netcat with UDP

Question

I noticed a strange behaviour working with netcat and UDP. I start an instance (instance 1) of netcat that listens on a UDP port:

nc -lu -p 10000
         


        

Answer 1

Having given up on netcat on my OS version this is pretty short and gets the job done:

#!/usr/bin/ruby
# Receive UDP packets bound for a port and output them
require 'socket'
require 'yaml'

unless ARGV.count == 2
  puts "Usage: #{$0} listen_ip port_number"
  exit(1)
end
listen_ip = ARGV[0]
port = ARGV[1].to_i

u1 = UDPSocket.new
u1.bind(listen_ip, port)
while true
  mesg, addr = u1.recvfrom(100000)
  puts mesg
end