Greetings! You may find this problem little strange. But is true. If you could guide me / help me, I would be very grateful to you!
Thanks in Advance!

We have two systems:

A : Running windows server with IP Address
B : Running Ubuntu 12.04 LTS on a virtual machine. The NAT'ed address is (internal ip address is :

Till today, it was possible to send packets from B to A. Suddenly, from past 1-2 hours, we are not able to even ping from B to A.
Strangely, I am able to ping from A to B (I can see this in Wireshark installed on A).
And, they are on the same LAN. Strangely, again, I am able to RDP into A and SSH into B.
Both the machines can access internet in general.

What could be wrong at B (or, could be A also!) ?

Govinda Padaki