Without a detailed TCP trace I can't be sure but it sounds like perhaps you have a path MTU discovery problem between the server and client, or something similar. I suspect that when you turn on driver debugging, you will see the driver just stop receiving new data from the network at some point.
Exactly, the cause of the remote SELECT execution (through Internet) failure was the MTU. After decrease the MTU value in Kubuntu, the remote SELECT execution works fine.
