[ltp] WiFi on T42 (routing issues with eth0 and eth1)

[morpheus]

On Sat, 2005-01-15 at 16:55 -0800, ogjunk-linuxtp@yahoo.com wrote:
> I think my problem is even more basic. :)
> That is, if I take down eth0, bring up eth1, ensure the correct route,
> I still can't ping.... can't even ping the router:

Sorry, I thought you said in a previous post that if you set the IP
address of eth1 manually, you were able to ping the router.  Are you
saying that you can't do this:
# ping -I eth1 192.168.0.1

> # Remove the extra default route (the one that didn't use metric)
> [root@localhost otis]# route del default
> [root@localhost otis]# route
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric Ref    Use
> Iface
> 192.168.0.0     *               255.255.255.0   U     0      0        0
> eth1
> 192.168.0.0     *               255.255.255.0   U     0      0        0
> eth0
> 169.254.0.0     *               255.255.0.0     U     0      0        0
> eth0
> default         192.168.0.1     0.0.0.0         UG    1      0        0
> eth1
> default         192.168.0.1     0.0.0.0         UG    2      0        0
> eth0

Yes, this looks perfect.  You have no problem with the routing table.
It seems we're back to diagnosing a simple connectivity issue between
the interface and the access point.

> [root@localhost otis]# ping 66.94.234.13 -I eth1
> PING 66.94.234.13 (66.94.234.13) from 192.168.0.3 eth1: 56(84) bytes of
> data.
> >From 192.168.0.3 icmp_seq=1 Destination Host Unreachable

Even more evidence to confirm the above.  However, if you could run:
# traceroute -i eth1 66.94.234.13
We can know for sure.

> Don't my routing tables look correct now?

Yes, definitely.

> > You could use different subnets...but this doesn't seem to be an
> > option for you since your AP is on the same subnet as your wired LAN.
> 
> My AP's IP is: 192.168.0.1.  eth0 is 192.168.0.2 and eth1 is currently
> 192.168.0.3.  I could manually set the IP for eth1 to be, say,
> 192.168.1.3, if that would make things easier.

You'd also have to change the IP of the AP to the 192.168.1.0 subnet. If
the AP has a built-in router, you can then have it route your packets to
the 192.168.0.0 subnet.  However, as your problem now appears to be the
connection between the AP and the IF, I would hold off on doing this
since it will probably not solve the problem.

> Well, let me thank you one more for your patience!  I really appreciate
> it.  Would you (or anyone else) happen to have an example of a routing
> table with both eth0 and eth1/wlan0 on the same subnet and going out
> through the single gateway, so that packets go over either eth0 or
> eth1, depending on whether the computer is plugged into the network or
> is near an AP?

Your routing table as posted here looks fine.  To summarize, with the
routing table set as shown above, please provide the following info:
1. Results of: # ping -I eth1 192.168.0.1
2. Results of: # traceroute -i eth1 192.168.0.1
3. Results of: # ifconfig
4. Results of: # iwconfig
5. Is your AP also your router?  A quick "sketch" of how everything is
connected would help.

We're getting closer to the answer...I don't think the issue is with the
routing table.

-m