following Takahashi-san's advice I connected PC, controller and network cable to the same Ethernet hub. The ping still fails. BUT if I unplug the nework cable, which means I isolate my system from NAOJ network, then I get this ping returns:
Pinging 10.68.10.241 with 32 bytes of data:
Reply from 133.40.117.65: Destination host unreachable.
Reply from 133.40.117.65: Destination host unreachable.
Reply from 133.40.117.65: Destination host unreachable.
Reply from 133.40.117.65: Destination host unreachable.
Ping statistics for 10.68.10.241:
Packets: Sent = 4, Recieved = 4, Lost = 0 (0% loss),
In the case of 192.168.11.121-IP controller the ping still fails, even in the isolated case.