Force iperf traffic to eth0

I'id like to force the traffic to one of the IP address of my server
to through thesecond one.

Server got 2 ethernet interfaces, eth0 (192.18.12.1) and eth1
(192.18.14.1). The aim is to run iperf and others tools from
192.18.12.1 to 192.18.14.1 in such configuration :

eth0 <------> { Network } <-----> eth1

#iperf -s (force listening on eth1)
#iperf -c 192.18.14.1 (force sending on eth0)

The problem I have is I cannot tell iperf to listen or send trafic
through an interface in particular. I've tried with tcpreplay, but I
cannot reach 1Gbit/s with it, limited near 600Mbit/s, don't know why,
maybe RAM speed or something like that.

Thanks

cmucchietto@gmail.com wrote:
> I'id like to force the traffic to one of the IP address of my server
> to through thesecond one.
>
> Server got 2 ethernet interfaces, eth0 (192.18.12.1) and eth1
> (192.18.14.1). The aim is to run iperf and others tools from
> 192.18.12.1 to 192.18.14.1 in such configuration :
>
> eth0 <------> { Network } <-----> eth1
>
> #iperf -s (force listening on eth1)
> #iperf -c 192.18.14.1 (force sending on eth0)
>
> The problem I have is I cannot tell iperf to listen or send trafic
> through an interface in particular. I've tried with tcpreplay, but I
> cannot reach 1Gbit/s with it, limited near 600Mbit/s, don't know why,
> maybe RAM speed or something like that.

You cannot.

For this kind of testing, you'll need at least
two computers.

The IP stack is smart enough to route traffic to ALL
local IP addresses via the loopback interface, lo.

This also includes the you cannot test the local
NIC's and their drivers by sending to any of the
addresses of the same host.

This is a FAQ, coming up every few weeks in slightly
different forms.

--

Tauno Voipio
tauno voipio (at) iki fi