Jack writes:

> Suppose two IP addresse are assigned to one PC NIC.
> What will happen when the PC connect to internet?

I assume you're wondering which source address will be picked for
outgoing packets. It depends on the OS, but generally, if the
application specifies a local address to be used, that address will be
used. If the destination address is on the same subnet as one of the
IP addresses but not the other, that IP address will be used.
Otherwise, the OS will pick one of the addresses as the default
(usually the first) and use that as the source address.

Hope this helps,

----Scott.

On Nov 5, 1:50 pm, Jack wrote:
> Suppose two IP addresse are assigned to one PC NIC.
> What will happen when the PC connect to internet?

All h*ll breaks loose and the PC kills the entire internet. Darkness
falls and the end of humanity follows shortly thereafter.

Actually, you haven't given us enough info to provide a proper
projection. The effect can range from "absolutely nothing happens at
the PC, and the internet proceeds onward without even noticing"
through "routing at the PC's local segment gets royally fouled up and
that segment loses connectivity".

On Mon, 05 Nov 2007 15:15:16 -0500, Scott Gifford wrote:

> Jack writes:
>
>> Suppose two IP addresse are assigned to one PC NIC. What will happen
>> when the PC connect to internet?
>
> I assume you're wondering which source address will be picked for
> outgoing packets. It depends on the OS, but generally, if the
> application specifies a local address to be used, that address will be
> used. If the destination address is on the same subnet as one of the IP
> addresses but not the other, that IP address will be used. Otherwise,
> the OS will pick one of the addresses as the default (usually the first)
> and use that as the source address.

As the OP seems to be using Windows, we can tell that an appropriate IP
will be picked according to what you layout above. Lately I haven't come
across an OS that does not do the "right thing". Earlier (much earlier)
versions of HPUX used to pick the first address assigned to the NIC as
the source address. Needless to say, this was not the right thing to do
if sending to the subnet of the second IP and those subnets weren't the
same (and no route back existed).

M4