> cbrown@denalics.net (Christopher E. Brown) writes:
>
> > Example, machines A,B,C all have the same IP on a lookback or
> > dummy interface. A load director/etc is currently routing all traffic
> > to the cluster IP to machine A.
> >
> > Should machine Bs interface get into PROMISC mode all packets
> > (even though they are sent to another MAC addr) will hit the IP layer,
> > and should the IP be found on a local interface, the machine will
> > respond.
>
> This is not true. When an interface in promisc mode receives a packet
> not destined at its MAC address and not a {broad,multi}cast it sets its type
> to PACKET_OTHERHOST. arp_rcv ignores such packets. IP does the same check.
>
> -Andi
Hmm, I have not rechecked this in 2.2.x, however with <= 2.0.x
this was not so.
When an interface in promisc mode received a packet destined
for another mac, but to an IP the local host owns it would, as you
said, not arp. It *would* respond to the packets though.
To restate, it was assumed that anything with a locally owned
IP that made it to the IP layer was ours. Should one have an
interface in promisc, where we receive a packet with an IP we have but
destined to another MAC addr it would get passed to the IP layer, and
dealt with exactly as if it was sent to our MAC addr.
---
As folks might have suspected, not much survives except roaches,
and they don't carry large enough packets fast enough...
--About the Internet and nuclear war.
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