[CentOS] Networking just stopped working

Thu Jul 8 05:32:40 UTC 2010
Kahlil Hodgson <kahlil.hodgson at dealmax.com.au>

On 08/07/10 14:58, Christopher Chan wrote:
>> If you have two machines on the same network with the same IP address
>> you get behaviour like this.  Had this happen once when an engineer
>> reset a UPSs and it took on the IP address of a main switch.
>> arpwatch is your friend.
> Unfortunately all addresses, both internal and Internet, on this box are 
> static and assigned so there is no hope of a collision. The dhcp server 
> does not serve any address in the same range that the box uses internally.

I was referring to the case where another box (or network device) on the
same network (i.e. plugged into the same switch/router/hub) has been
given a static IP address the same as that used by the problem box.
This could be a new server, a printer, a UPS, or any number of other
network devices.  It could also be a device being reset to factory
settings which conflicts with the problem box.

I'm you have another Linux machine on the same network that is not
having the same problem, try installing arpwatch.  It should pick up the
conflict with 30mins or so.