DHCP setting, unplug ethernet cable and reset

Hi

Right now I am having problem DHCP operation.
After I set DHCP configuration, I detected dynamic IP address, and it’s working properly.

When I unplug Ethernet cable, netsilicon is restarted by reset couple of minute later.

How do I avoid this issue ?

Thanks

I also have the problem, but no reset before I update the firmware with patches. Anybody can tell me the reason?