Windows box shows "Network cable unplugged" when hooked up to my Linux router

drkstr · 10-03-2006, 01:02 PM

Bleh, this is why I don't use windows any more

I am hooking my mom up to my Linux router to share my internet connection but windows XP is saying that the network cable is unplugged.

This is the setup:

Windows --> eth1 --> iptables --> eth0 --> modem

My Linux box works just fine on the same setup. It's been awhile since I've used Windows so I am a little unfamiliar with it. Is there anything extra I need to do to get it to recognize the existence of my Linux box? I've tried telling windows to use DHCP, static, and played around with the duplex settings to no avail.

Any advice?

Thanks!
...drkstr

**edit**
FYI: windows box is go when I plug it directly into the modem, so it's not the cable.

marozsas · 10-03-2006, 01:15 PM

If you are connecting one pc to another directly, without a hub/switch, than the cable must be a cross-over cable. The straight cable will not work.

For reference, the cross-over cable has the following diagram:
1 ---> 3
2 ---> 6
3 ---> 1
4 ---> 4
5 ---> 5
6 ---> 2
7 ---> 7
8 ---> 8

drkstr · 10-03-2006, 02:07 PM

Thanks for the reply!

I admit, I know very little about networking so you are probably right. But I am curious why my Linux desktop can connect strait to my Linux router with the same eth cable.

Also, to make things even more confusing (for me at least) I brought my laptop into the mix for some testing, and this is what happened when moving the same ethernet cable around and testing connection by ssh'ing

Desktop eth0 --> server eth1 : Connects OK
Laptop eth0 --> desktop eth0 : Connects OK
Laptop eth0 --> Server eth1 : Does not Connect

So it appears my server will only accept connections from my Linux Desktop through eth1. Any idea what is causing this? (note: iptables is turned off on all machines during testing)

Thanks for the help!
...drkstr

setup:

Router:
eth0 - temporarily disabled while testing
eth1 - static

Code:

root@srv:~# ifconfig
eth1      Link encap:Ethernet  HWaddr 00:0C:41:EF:B0:07
          inet addr:192.168.1.1  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3038091 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1094646 errors:5 dropped:0 overruns:0 carrier:5
          collisions:0 txqueuelen:1000
          RX bytes:3714588850 (3542.5 Mb)  TX bytes:999745566 (953.4 Mb)
          Interrupt:10 Base address:0x1400

Code:

root@srv:~# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo

Desktop:
eth0 - static

Code:

root@dsk:~# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0D:56:02:64:7E
          inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1095334 errors:3 dropped:0 overruns:0 frame:3
          TX packets:3038761 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1004348400 (957.8 Mb)  TX bytes:3726864511 (3554.2 Mb)
          Base address:0xdf40 Memory:feae0000-feb00000

Code:

root@dsk:~# route -n
Kernel IP routing table
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
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
0.0.0.0         192.168.1.1     0.0.0.0         UG    1      0        0 eth0

laptop
eth0 - static

Code:

root@lpt:/etc/rc.d# ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:46:1D:11:16
          inet addr:192.168.1.102  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1087 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1088 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:184020 (179.7 KiB)  TX bytes:112168 (109.5 KiB)
          Interrupt:10 Base address:0x1800

Code:

root@lpt:/etc/rc.d# route -n
Kernel IP routing table
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
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
0.0.0.0         192.168.1.1     0.0.0.0         UG    1      0        0 eth0

marozsas · 10-03-2006, 03:40 PM

Quote:

Originally Posted by drkstr

But I am curious why my Linux desktop can connect strait to my Linux router with the same eth cable.

Some ethernet cards has the capability to auto-detect cross/straight cables and work with both.

In your scenario, looks like the linux desktop has that kind of card, and both windows desktop and the laptop, hasn´t.
The windows message about the cable is unplugged is typical.

Besides that, your configuration looks like fine to me.

Try to connect using a hub/switch and straight cables you already have, or buy a cross-over cable.

good luck !

michaelk · 10-03-2006, 03:58 PM

When not using a hub/switch the adapters must be configured for the same settings i.e. 100MB full duplex. The default is typically is auto negotiate. Check the properties in windows and use the mii-tool in linux. mii-tool will also verify that you have a good link.

drkstr · 10-03-2006, 04:44 PM

Ok, makes sense to me now. Thanks for the help everybody, I have to take off for a bit, but I'll try messing around with the pairings (terminology?) when I get home. I have a switch coming in the mail in a few days, but I need to try and get something working in the mean time. I'll let you know how it turns out.

Thanks again!
...drkstr