Re: Problem using 3 ethernet cards
On Fri, Feb 11, 2000 at 05:35:02PM -0200, paulo henrique castro wrote:
> Dear Friends,
>
> I still have this problem:
>
> I have a Debian Linux with 3 ethernet cards:
>
> eth0 - 192.168.0.1
> eth1 - 192.168.0.2
> eth2 - 192.168.0.3
>
> All cards connected in the same HUB..
> When I ping from another computer (conected on same hub too!) to
> 192.168.0.1 its work fine!! The same for .2 and .3 IPs..
>
> But, when I disconect the cable from eth0 and try ping 192.168.0.2 or
> 192.168.0.3 I dont receive any reply, even still being connected!!!
The problem is that under 2.2 ALL interfaces reply to arp requests for
ANY connected ip address - That means that eth0 is the fastest card
and thought replys first on arp requests - Though ALL traffic flows
in through eth0 - If you now disconnect eth0 everything fails until
the arp caches expire.
Another problem might be that the linux kernel has its default and network
route only over eth0 (You may not set the same route to a different interface)
so you fail because the network route to your network is on a dead interface.
There is no real clean way to connect multiple ethernets cards to the same
subnet - only hacks - which require DEEP knowledge of arp, ip and routing.
The correct way to get more bandwith to a single subnet is 100/1000MBit ethernet
or Channel bundling (like Fast Etherchannel and the according 802.1X
standard i have forgotten) but this is unimplemented for the Linux kernel
afaik ...
Flo
--
Florian Lohoff flo@rfc822.org +49-5241-470566
"Technology is a constant battle between manufacturers producing bigger and
more idiot-proof systems and nature producing bigger and better idiots."
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