Basic network setup problem

I've just done an install of Fedora2 on a machine which is connected via
a dumb hub to a windows box.

Fedora box : 10.0.0.100 netmask 255.255.255.0
Windows box: 10.0.0.151 netmask 255.255.255.0

However, I can't do a basic ping from one box to the other. I ran
ethereal on the Fedora box and did a ping to that box from the windows box.
This shows up in ethereal as an ARP request
Who has 10.0.0.151? Tell 10.0.0.100

Not being the brightest networking spark, this looks to me like the ping
from the windows box has gotten as far as the Fedora box, but the Fedora
box doesn't know where to send the reply back to?

Any ideas?

just a thought, can you please check the default firewall settings in
fedora? Redhat used to make their distros with some basic firewall
rules with iptables ...

just do a listing ... and let me know.

#iptables -L -n

raqueeb hassan
bangladesh

Fatted,

A couple of thinks you might want to check.

1) Check that you don't have a firewall on either PC that blocks ICMP
(the protocol used with PING). If your Windows box is XP it's got a
built-in firewall similar to the firewall in Fedora.
2) Ensure that the ethernet card on the Fedora box is UP. You can check
this with ifconfig.
3) See if, at each computer you can PING the loopback address of 127.0.0.1.
4) See if, at each computer you can PING its own address (i.e. at the
Fedora PC try to PIN 10.0.0.100 and at the Windows machine try to PING
10.0.0.151).
5) Check to make sure that your dumb hub is not really smarter than you
think--make sure it doesn't have routing capabilities with a firewall
capability,

Good luck.

Regards,

Richard Huelbig

Fatted wrote:
> I've just done an install of Fedora2 on a machine which is connected via
> a dumb hub to a windows box.
>
> Fedora box : 10.0.0.100 netmask 255.255.255.0
> Windows box: 10.0.0.151 netmask 255.255.255.0
>
> However, I can't do a basic ping from one box to the other. I ran
> ethereal on the Fedora box and did a ping to that box from the windows box.
> This shows up in ethereal as an ARP request
> Who has 10.0.0.151? Tell 10.0.0.100
>
> Not being the brightest networking spark, this looks to me like the ping
> from the windows box has gotten as far as the Fedora box, but the Fedora
> box doesn't know where to send the reply back to?

Actually the ping (which would be ICMP traffic) is never sent. The
first thing the Fedora box has to do is determine the Windows' MAC
address. That's what ARP does. Except the Windows box never answered.
Cables could be bad; hub or NICs could be dead or misconfigured;
routing could be screwed up; etc.

Allen Kistler wrote:
> Fatted wrote:
>
>> I've just done an install of Fedora2 on a machine which is connected
>> via a dumb hub to a windows box.
>>
>> Fedora box : 10.0.0.100 netmask 255.255.255.0
>> Windows box: 10.0.0.151 netmask 255.255.255.0
>>
>> However, I can't do a basic ping from one box to the other. I ran
>> ethereal on the Fedora box and did a ping to that box from the windows
>> box.
>> This shows up in ethereal as an ARP request
>> Who has 10.0.0.151? Tell 10.0.0.100
>>
>> Not being the brightest networking spark, this looks to me like the
>> ping from the windows box has gotten as far as the Fedora box, but the
>> Fedora box doesn't know where to send the reply back to?
>
>
> Actually the ping (which would be ICMP traffic) is never sent. The
> first thing the Fedora box has to do is determine the Windows' MAC
> address. That's what ARP does. Except the Windows box never answered.
> Cables could be bad; hub or NICs could be dead or misconfigured;
> routing could be screwed up; etc.

Or an idiot is in charge The Fedora box has 2 nics, and yes ladies
and gentlemen I plugged the wire into the wrong nic. What was throwing
me off (even more than my own cleverness) was that I could see the ARP
messages via Ethereal, but couldn't figure out why they weren't pinging.

However this does lead me to the question, how does the Fedora box know
that it needs to determine the windows MAC address (i.e. "the Who has
10.0.0.151? Tell 10.0.0.100" stuff) if the ICMP traffic wasn't arriving
correctly?

On Mon, 05 Jul 2004 10:22:29 +0200
Fatted <(E-Mail Removed)> wrote:


> Or an idiot is in charge The Fedora box has 2 nics, and yes ladies
> and gentlemen I plugged the wire into the wrong nic. What was throwing
> me off (even more than my own cleverness) was that I could see the ARP
> messages via Ethereal, but couldn't figure out why they weren't pinging.
>
> However this does lead me to the question, how does the Fedora box know
> that it needs to determine the windows MAC address (i.e. "the Who has
> 10.0.0.151? Tell 10.0.0.100" stuff) if the ICMP traffic wasn't arriving
> correctly?

That's how Ethernet works. Every Host has an Arp-table, with
IP-adresses corresponding to MAC-Adresses. If the Adress is inside
of the Network the host is connected to, Packets are adresses by
MAC-Adress, and if the Host don't have an entry for the IP-Adress,
it sends as broadcast a ARP Who has <IP-Adress> tell <me>. The Host
that has the Adress responds with the MAC-Adress it's got. Then the
first Host can send the ICMP echo-request to the Mac-adress.

Greets
Chris