On Thu, 06.03.08 13:51, John W. Linville (linville(a)redhat.com) wrote:
> I'm sorry, but that's just wrong. Setting a net route on
a broadcast
> device will cause ARP request for the IP addresses in that network
> to be broadcast on that segment. Nothing more, nothing less. A host has
> to respond to these requests for routing to occur (most likely though
> proxy arp). The only thing being sent with a broadcast MAC are the ARP
> requests, but those are always sent this way.
Ralf is, of course, correct. [1] In a sense the only purpose of
the routing table is to control which IP address gets ARPed when
sending-out a frame. Setting the default route to "dev eth0" just
means you ARP for any address.
Just to make sure, I replicated this environment on my local LAN.
Simply setting the default route as "dev eth0" left me with a laptop
that could only reach the local LAN. Turning on proxy arp at my NAT
router enabled me to communicate with the Internet. I encourage you
to replicate my experiment. :-)
It's possible that there is some other setting that turns-on the
behavior you describe. But if there is, I don't know about it.
Thanks,
John
[1] Conveniently, that means I am correct as well. :-)
Of course, you two are absolutely correct. My bad. I guess I shouldn't
claim things without checking them first ;-)
But still, enabling this kind of routing on the gateway is just a
matter of doing:
echo 1 > /proc/sys/net/ipv4/conf/eth0/proxy_arp
echo 1 > /proc/sys/net/ipv4/conf/eth0/forwarding
Right?
Lennart
--
Lennart Poettering Red Hat, Inc.
lennart [at] poettering [dot] net ICQ# 11060553
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