First of all sorry if this is not the right list for this question/doubt.
I noticed a while ago that I can ping a machine on a diferent network, with no
IP on that network, if I have a network interface on the same broadcast domain
as that machine's interface if I add a route to that IP through the local IP in
the same broadcast domain.
Did I make myself clear ? :)
Well, what I have is this:
/--------\
| | /--------\
| Linux1 |-- aaa.bbb.ccc.ddd/24 -----| Switch |
| | \--------/
\--------/ |
|
eee.fff.ggg.hhh/24
|
/---------\
| |
| Linux2 |
\___________/
(aaa.bbb.ccc.0) != (eee.fff.ggg.0)
Linux1 should not be able to ping Linux2 except through a gw, right?
(They're not on the same network so the packet should go through the
default gw if a less generic route isn't defined, of course)
And the packet should go on until it reached a router/gw with a IP
on the eee.fff.ggg.0/24 net and it would then be delivered to
eee.fff.ggg.hhh.
The problem is that the linux stack seems to completely "short circuit"
from layer 3 to layer 2 if I add a gw to eee.fff.ggg.hhh through
aaa.bbb.ccc.ddd (route add -host eee.fff.ggg.hhh gw aaa.bbb.ccc.ddd);
it issues an arp request regardless if the destination
IP is on the local network or not.
Is this a correct behaviour? Am I missing something?
Note: this only happens between 2 linuxes, I tried between 2 FreeBSDs
but the IP stack behaves diferently.
TIA.
--
Jose Celestino <japc@co.sapo.pt> Systems::SAPO.pt http://www.sapo.pt
---------------------------------------------------------------------
Titanic 1912 / Hindenburg Zeppelin 1937 / Microsoft Windows 2000
OpenBSD claudia 3.0 GENERIC#94 i386
