Disable Route Optimization in Linux

[Tony Arnold]

Bruce,

Bruce wrote:
> Greetings,
> 
> I'm working toward building up a couple of test fixtures that require me 
> to generate multiple channels of Ethernet traffic.  I have some Perl 
> code that will allow me to send and receive traffic using specified 
> local and peer ports.  I seem to have only one problem that is 
> preventing me from getting started.  Linux is optimizing all my traffic 
> to go through the default port.
> 
> To be more specific, let's assume I have a 8 port switch to be tested.  
> Assume I have two Linux boxes with a quad NIC card in each.  Assume the 
> 8 ports from the two quad NIC cards all get plugged into the switch.  To 
> test each switch port I need to be able to generate traffic from all 8 
> ports of the two quad NIC cards.  Linux optimizes my routes and sends 
> all traffic through the default eth port, even when I specify another port.
> 
> Is there any way to turn off the router in Linux or at least override it 
> with my desired routes?  I have tried many combinations of "route add", 
> "route del", "ip route add x.x.x.x via y.y.y.y.  So far I am striking 
> out.  Any help would be appreciated.

Do you have different networks numbers (i.e., logically and the netmask
with the ip address and you should get a different answer for each
interface) on each interface to make sure they are effectively on
different networks so far as IP is concerned? You would also need to set
up routes for each network/interface.

Regards,
Tony.
-- 
Tony Arnold, IT Security Coordinator, University of Manchester,
IT Services Division, Kilburn Building, Oxford Road, Manchester M13 9PL.
T: +44 (0)161 275 6093, F: +44 (0)870 136 1004, M: +44 (0)773 330 0039
E: tony.arnold at manchester.ac.uk, H: http://www.man.ac.uk/Tony.Arnold