Arduino uno with ethernet hangs?

Goodevening,
the crashes are not often and the goal i have is to find all the possible solutions that will imporve the QoS of the infrastructure i am developing. Furthermore, i also have no doubt that the arduino device is well developed and works perfectly. As far as the previous crash is concerned i found a very small but crucial error. If you have not pointed out that, statistically, ethernet shield is steady i would have thought that it was the arduino.

As far as the the way that the connection to the serial port is being created and the reboot of the Arduino is triggered can you, SurferTim, give more details. I understand what you are suggesting but i want to see the details of your implementation.

Thank you all for your help and your support
ioigoume