require 'socket'

server = TCPServer.new('0.0.0.0', 24000)
loop do
  Thread.start(server.accept) do |client|
    if (ping = client.gets) =~ /PING/
      puts 'server: RECV PING'
      client.puts("PONG\n")
    else
      puts "server: RECV #{ping}"
      client.puts("NOPE\n")
    end
    client.close
  end
end