Re: 2 NIC's on same network, possible?

[thedistance <thedistance () 1thedistance com>]

There are two ways to do this correctly. (May be more, but only 2 I know
of)

1. If you have a switch that can do port-trucking then download the
latest Ethernet bonding patch and bond the interfaces. (I suggest that
you use the latest bonding patch because the code in the kernel is
flakey last time I checked)

2. Install iproute2. With iproute2 you can have seperate routing tables
for each interface and then set a default route that load balances the
interfaces for outbound traffic.

Both solutions give you increased throughput.

td

On Tue, 2003-07-29 at 06:15, Ansgar Wiechers wrote:
> On 2003-07-27 Vineet Mehta wrote:
> > My collegue has a Linux machine which has 2 NIC's on it. What he did
> > was assign the IP's 192.168.0.6/24 and 192.168.0.7/24 to the NIC's.
> > And he was trying to ping the network but was getting errors (i dont
> > know the errors).
> >
> >                -----------------
> >               | Switch          |
> >               |_________________|
> >                 |             |
> >                 |             |
> >                 |             |
> >           -------------------------------
> >           |  NIC1            NIC2       |
> >           |192.168.0.6/24 192.168.0.7/24|
> >           |        Machine              |
> >           |-----------------------------|
> >
> > I tried explaining him like this:-> 
> >
> > Configuring the machine's network like this is not a big problem, coz
> > other machines on the network can still see these 2 IP's. But his
> > machine will not be able to reach other machines on the network coz 2
> > NIC's point to the same network so Linux kernel would be confused for
> > which NIC to use to send packets.
>
> Correct. Your machine can't have two routes pointing towards the same
> network.
>
> > If by any means we set the route to use ANY one NIC to reach the
> > network then there will be no errors.
>
> Probably (not sure about that). But you will at least double the traffic
> your machine causes (provided it works at all).
>
> > Am i right in this, or this is not possible AT ALL? I took my thought
> > from the concept of IP Aliasing.
>
> Why would he want to connect two Interfaces to the same network? The
> only reason I can think of is port-trunking, but in that case the
> operating system would handle both interfaces as one (AFAIK).
>
> Regards
> Ansgar Wiechers
>
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