2 routes to a single end point ?

I would like to know whether it is possible to define two direct routes
from a machine with two interfaces to a single other machine :

Machine src Machine dst
eth0 _____
\____
____| dst0
eth1 _____/


I tried bonding, coupling eth0 and eth1 in a master bond0. It worked fine
but it is not what I want to do since the traffic is shared between the
two slaves.

I tried a slightly different configuration : the destination having also
to interfaces dst0 and dst1. With iproute2 I successfully set up two
parallel routes eth0-dst0 and eth0-dst1. But again, it is not what I want.

Finally, using 'ip route add,change, ...' I've tried to configure my
system in order to have the traffic going directly from eth0 to dst0
*or* (exclusive) from eth1 to dst0. But 'ip route' has not accepted my
requests.

Is it a forbidden configuration ?

"Jean-Paul Le Fevre" <lefevre@hep.saclay.cea.fr> wrote in message
news:403DC941.9080502@hep.saclay.cea.fr...
> I would like to know whether it is possible to define two direct routes
> from a machine with two interfaces to a single other machine :
>
> Machine src Machine dst
> eth0 _____
> \____
> ____| dst0
> eth1 _____/
>
>
> I tried bonding, coupling eth0 and eth1 in a master bond0. It worked fine
> but it is not what I want to do since the traffic is shared between the
> two slaves.
....
> Is it a forbidden configuration ?

I'm certainly no expert, but isn't this a job for IP Masquerading?
http://www.tldp.org/HOWTO/Masqueradi...WTO/index.html

Good Luck!
Rich

Jean-Paul Le Fevre <lefevre@hep.saclay.cea.fr> wrote:
> I would like to know whether it is possible to define two direct routes
> from a machine with two interfaces to a single other machine :
>
> Machine src Machine dst
> eth0 _____
> \____
> ____| dst0
> eth1 _____/

In order to help you, I would need to ask you why you wanted to do this.
That would help clarrify the situation.

--
Cameron Kerr
cameron.kerr@paradise.net.nz : http://nzgeeks.org/cameron/
Empowered by Perl!

Cameron Kerr wrote:
> Jean-Paul Le Fevre <lefevre@hep.saclay.cea.fr> wrote:
>
>>I would like to know whether it is possible to define two direct routes
>>from a machine with two interfaces to a single other machine :
>>
>> Machine src Machine dst
>> eth0 _____
>> \____
>> ____| dst0
>> eth1 _____/
>
>
> In order to help you, I would need to ask you why you wanted to do this.
> That would help clarrify the situation.
>

Some colleagues of mine want to test a set of switch devices.
Actually the architecture is the following :

The source consists of something like 6 interfaces (100 Mb/s)
embedded in 1 or 2 PC.
The destination is a machine with 1 Gigabit/s interface.
A java application is running between the source and the destination
sending data back and forth.
The device to verify is inserted bewteen the source and the destination.
It has 6 input ports and 1 output port.

The goal is to see whether the switch hardware is functionning as
specified and more specifically if the ports are correctly wired.
So it is quite important to know which route (i.e. which port) is chosen.



--
__________________________________________________ _________________

Jean-Paul Le Fèvre * Mail : LeFevre@fonteny.org

Jean-Paul Le Fevre <jeanpaul.lefevre@free.fr> wrote:
> Cameron Kerr wrote:
>> Jean-Paul Le Fevre <lefevre@hep.saclay.cea.fr> wrote:
>>
>>>I would like to know whether it is possible to define two direct routes
>>>from a machine with two interfaces to a single other machine :
>>>
>>> Machine src Machine dst
>>> eth0 _____
>>> \____
>>> ____| dst0
>>> eth1 _____/

Well then, you would need to put static routes on the destination, so
that every IP has its own route, directing it to the correct address.

--
Cameron Kerr
cameron.kerr@paradise.net.nz : http://nzgeeks.org/cameron/
Empowered by Perl!

Cameron Kerr wrote:
> Jean-Paul Le Fevre <jeanpaul.lefevre@free.fr> wrote:
>
>>Cameron Kerr wrote:
>>
>>>Jean-Paul Le Fevre <lefevre@hep.saclay.cea.fr> wrote:
>>>
>>>
>>>>I would like to know whether it is possible to define two direct routes
>>>
>>>>from a machine with two interfaces to a single other machine :
>>>
>>>> Machine src Machine dst
>>>> eth0 _____
>>>> \____
>>>> ____| dst0
>>>> eth1 _____/
>
>
> Well then, you would need to put static routes on the destination, so
> that every IP has its own route, directing it to the correct address.
>
How ?

With route(8) it seems that, if you define 2 static routes to the
same target, the system uses only the first one.

On the other hand, with iproute2, I could not find the corrrect arguments
to 'ip route add ' to set up the 2 routes. The command failed with a
error message.


--
__________________________________________________ _________________

Jean-Paul Le Fèvre * Mail : LeFevre@fonteny.org

Jean-Paul Le Fevre <jeanpaul.lefevre@free.fr> wrote:
> Cameron Kerr wrote:

>> Well then, you would need to put static routes on the destination, so
>> that every IP has its own route, directing it to the correct address.
>>
> How ?
>
> With route(8) it seems that, if you define 2 static routes to the
> same target, the system uses only the first one.

Ah, a good point. You can use IP aliases on dst so it has multiple IPv4
addresses.

root@dst:~# ifconfig eth0:1 <IP1> netmask 255.255.255.255 up
root@dst:~# ifconfig eth0:2 <IP2> netmask 255.255.255.255 up

Each <IPx> would need to be different though, and the Java program would
need to know to send to the correct IP address.

--
Cameron Kerr
cameron.kerr@paradise.net.nz : http://nzgeeks.org/cameron/
Empowered by Perl!