Checking if a TCP port is in use

port_open.rb

def is_port_open?(ip, port)
  begin
    Timeout::timeout(20) do
      begin
        s = TCPSocket.new(ip, port)
        s.close
        return true
      rescue Errno::ECONNREFUSED, Errno::EHOSTUNREACH
        return false
      end
    end
  rescue Timeout::Error
  end

  return false
end