On Mon, Mar 05, 2001 at 04:38:10PM -0600, [EMAIL PROTECTED]
wrote:
> Now, back to the original discussion of a router sharing the same IP
> address as (in this example) the originating host.
Actually, the original discussion was regarding the use of private IPs
on public routers. It was mouss who brought up the special case of the
sender using the same private IP as the router.
> Without testing this in
> the lab I believe that this should not be a problem for the router.
The
> router will, when decrementing to a TTL=0, respond with an ICMP
message
> with the source and destination IP addresses set the same (e.g.
10.1.1.1).
So far, so good.
> I suspect the router will faithfully pass this out the port that is
bound
> to the same IP address since it is not an internal route (e.g.
127.0.0.1 on
> Linux).
Wrong.
Any IP implementation I've seen in the wild will correctly identify such
a packet as being destined to the same host and will place the packet in
the inbound queue for the stack to process as if it had been handed to
it by the network driver.
A trivial exercise to see if this holds true for your OS is to ping your
hosts's own IP address while watching to see if packets are actually
pushed out your Ethernet interface. When I try this with Solaris, for
example, the packet is never handed to an Ethernet driver and is never
placed on the wire.
--
Devin L. Ganger <[EMAIL PROTECTED]>
A guy, his car, his miss, his nerve;
He kissed his miss and missed the curve.
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