[WBEL-users] Network Connectivity on WBEL 4

[Kirby C. Bohling]

On Sun, Jul 24, 2005 at 01:06:25AM -0500, Dan Herrstrom wrote:
> Greetings all.
> 
> I just installed WBEL 4 on my "server" box and for some reason I
> cannot get it to talk to my network. The machine has two cards, a
> Netgear FA311 10/100 and a Netgear GA311 Gigabit. I'm not sure exactly
> which one is which eth device but I have assigned the IP 172.16.1.2 to
> eth0 and 172.16.1.3 to eth1. If i give simply ping 172.16.1.2 or ping
> 172.16.1.3 it succeeds but if i give ping -I eth0 172.16.1.3 or ping
> -I eth1 172.16.1.2 i receive "Destination Host Unreachable". I also
> cannot ping this machine from my Windows 2000 workstation nor can I
> ping it from the server. It acts as though all the necessary modules
> are installed and I know the cards to be in working order as they
> worked fine when I had Fedora Core 2 installed on the machine. Any
> suggestions would be appreciated.
> 
> Thanks for your help..

You can start by running "ifconfig -a" or "ip addr show" as root.
Post that.  Then we can see how it's actually set up, not how you
describe it.  A lot of times, the mismatch between what you think
and what is, is the problem (that's not an insult, I've been bitten
enough times by this that I don't trust how I think something is
configured, I double check the tools agree with me).  Next, it'd be
helpful if you would describe the rest of the network, and how it's
configured TCP/IP and physically cabled.

I'm not shocked the "ping -I" failed.  You are forcing it to go out
the wrong interface.  On a machine I have handy with two interfaces:

(Output editted slightly to remove unimportant bits...)
[root at harrier ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    inet 10.10.2.18/16 brd 10.10.255.255 scope global eth0
[root at harrier ~]# ip addr show eth1
3: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    inet 10.15.0.2/16 brd 10.15.255.255 scope global eth1

[root at harrier ~]# ping -I eth1 10.10.2.18
PING 10.10.2.18 (10.10.2.18) from 10.15.0.2 eth1: 56(84) bytes of data.
>From 10.15.0.2 icmp_seq=1 Destination Host Unreachable
...

So I would ignore the "ping -I" symptoms if I were you.  I get the
same thing on a machine that works fine.

Next, the cards should have the MAC addr's printed on them.
Normally the output of "ip addr show" will show you both of them.
You can check that the physical card is the one you think it is to
ensure the interface you think is eth0 is in fact what the Linux
kernel things is eth0.

Next, did you turn any of the firewall security on?  I've seen many
a problem resolved by doing "service iptables stop".  When you
installed, generally the firewall by default is set fairly secure.
If you didn't turn it down, there are a lot of things that won't
work.  You will want to go back and re-secure the firewall later,
but that will at least help you identify that it is the firewall.
Everyone says "high" security on the firewall.  That always seems
like a good idea.  I always end up having to disable it, trouble
shoot my problem.  Poke the holes I need, enable the firewall again.

Finally, you might be looking in all the wrong places.  I've have
several times where "ping" didn't work not because the machine I
just setup was configured wrong.  The packets got off the new
machine and to the destination machine just fine.  However, the
existing machines couldn't route packets back, because it was
missing a route or something else was misconfigured.  So be aware of
that.  That handiest way to see that is to run a packet sniffer on
the destination.  The poor man's way of doing that is to watch the
blinky lights on the switches.

When all else fails, blame the wiring and switches...  Just today, I
had a networking problem that didn't make any sense.  I just
couldn't ping from one machine to the other.  Turns out I had a bum
switch from NetGear.  Took me 2 hours to track it down.  

Thanks,
    Kirby