Hi all
I'm having a very very strange problem and I need some help to figure it out.
Let's start with the basic data. Ubuntu 10.04 LTS updated.

uname -a
Linux Oliver3 2.6.32-45-generic #101-Ubuntu SMP Mon Dec 3 15:41:13 UTC 2012 i686 GNU/Linux

It updated also libraries and utilities.
Before the last update everything was working just fine.
After the last update (yesterday) everything still works but one machine in my network is not reachable anymore from this machine.
My network has all assigned IP manually.
The updated machine with Ubuntu 10.04 LTS, let's call it Alpha, has the IP of and the unreachable one, let's call it Omega, the IP
All the other machines in my network can access Omega withou problems, as Alpha was able to do before the update.

Is not a network problem, Alpha is connected to the network, can see and access all the machines BUT not Omega.
Ping, ssh, vnc, http, nothing.
I also connected Alpha to the same router of other machines.
Still nothing, so it must be something about Alpha and is not physical since I can see and connect with other machines and to internet from Alpha.
Only Omega become invisible to Alpha !!

I suspect that the last update mess up something in the network configuration of Alpha but I was unable to find something strange.

Any suggestions about how to find and fix this problem ?

Many many thanks !!