Dead end; setting up small network

[hwkc]

Im trying to set a small network but encounter some strange problem.

I've got three computers all running on SuSE 8.2. The one i use for server/firewall got three network interfaces which connects outwards the internet, to a second stationary computer and to third one (laptop).

The problem is that i can't connect to the server in any way from the second one(or from the server to the it), even if i set it up exactly like my laptop and use the same interface from server. The laptop connects fine to the server.

But the network interface of the second one seem intact as i can connect it outwards the internet connecting it directly with the main network cable (setting it up as only computer that is) The second dualboots to windows as well but no connection running from there either.

the server uses 192.168.1.1 netmask 255.255.255.0 for the local net
and the second one uses 192.168.1.2 netmask 255.255.255.0, with a default route 192.168.1.1

I have _no_ idea whats wrong and I would be very grateful for hints to lead me in the right direction...

[Hawg]

Are all you machines connected to a hub/switch? If you connect them together directly you will need a crossover cable.

[azambuja]

Like Hawg said, if you connect them directly you need a crossover cable. There's the physical part you should check (bad cable, bad hub port, maybe even bad nic on server/station). To avoid a lot of work just try bringing your laptop (wich is working right) to where the second computer is and try connection through the laptop with the same cable you use for the second (of course, you're gonna have to unplug the second for a minute while you test). If the laptop doesn't work there, it's most likely a physical problem.
Try that, if you already haven't, and let us know what happened.

Good luck,
Fernando Azambuja

[hwkc]

I don't use a hub, I just connect the computers together with a TP cable. My server connects to internet (ISP gateway), computer 2 and computer 3. The problem is that I even tried with the same cable and network interface on the server that works fine with the laptop. But it simple will not work with the second computer... no response what so ever. So it cant be the cable or the network interface on the server.

And the network interface on the second computer should be operational as I can use it to connect to the internet directly (network socket going to isp). I even tried installing another network interface to the second computer without result.

So might there be something else that could interfere with the connection if it isn't Cable, Network interface, normal ifconfig config or routing??? Especially since it seems that I'm running an exact configuration regarding 'ifconfig' and 'route' on the computer that works (laptop) and the one that doesn't (second one).

[cowanrl]

I'm a little confused on your set up there. Do you have 3 NICs in your server, one connects to the Internet, one connects to the laptop and the other connects to the other computer?

If so, it would be nice to see the output of the ifconfig command on all three of the computers. How about posting that here. Also, post the contents of the routing table from server. You can get the routing table by executing /sbin/route -n.

[hwkc]

Yes thats true. But Im sure my probelms isn't with the routing table or the ip-settings for the interfaces. If it was, it wouldn't have worked with any computer...

Since running connection to server from say computer A works with:
eth0 Link encap:Ethernet HWaddr 00:00:E2:60:8F:58
inet addr:192.168.1.3 Bcast:192.168.1.255 mask:255.255.255.0

Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0

simply unplugging network cable from this one to computer B running with the _exact_ same config won't work. Perhaps i've just missed something, but I find it really strange... thx for the help anyway. I'll see if i can't try something else...

[cowanrl]

Originally posted by hwkc
Yes thats true. But Im sure my probelms isn't with the routing table or the ip-settings for the interfaces. If it was, it wouldn't have worked with any computer...

Since running connection to server from say computer A works with:
eth0 Link encap:Ethernet HWaddr 00:00:E2:60:8F:58
inet addr:192.168.1.3 Bcast:192.168.1.255 mask:255.255.255.0

Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0

simply unplugging network cable from this one to computer B running with the _exact_ same config won't work. Perhaps i've just missed something, but I find it really strange... thx for the help anyway. I'll see if i can't try something else...

Which computer was this output taken from?

From what little information you have provided, it looks like you have both interfaces that connect to your internal network on the same subnet. If so, that won't work.

I repeat my request for the information asked for in my previous post.

[hwkc]

Yes I know, but as i said it wasn't a routing or ip configuration problem, I just these configs for debugging cable and NICs. But I tried what someone suggested earlier with another cable and it worked fined. Turned out that it wouldn't work with a UTP cable so I tried a shielded one.

But I still find it strange that the UTP cable worked between some other machines, still burried in the nest of cables as when tried with the non working one, oh well... everything works fine now at least.

Thanks for all your help.

[hwkc]

I took a little closer look at the NICs and discovered that the NIC at one computer failed to light up when it was connected to the server machine, but when connected directly to the line going out to internet or my laptop computer it lighted up fine. So this is what problem seems to be. However I am unsure what really causing this problem or what the solution to it would be. So my question is really what makes the light go on. I realise this isn't really a linux related question, but I figured that u probably knew anyway...

(By the light i mean the light that would light up if connected to something, not the transfer light twinkle)

[DMR]

Assuming you're talking about the "link" LED, that just indicates that a valid network connection has been established between two devices. That is, the two devices have performed a digital "handshake" and acknowledged each other.

Lack of link can be caused by a number of factors including faulty circuitry, a bent or broken pin on one of the connectors, a defective or poor-qality cable, a bad crimp on one of the cable's RJ-45 connectors, a mis-wired cable, excessive electrical interference, or corruption of TCP/IP stack (the networking software).