Cannot get two Linux servers to talk to each other...

[DCCoolBreeze]

I have just built 2 Linux servers using RedHat 7.1. I set them up as file servers. Then I setup the NIC cards as

Server 1: etho 192.168.1.1
Server 2: etho 192.168.1.2

Next I "Ping"ed them and got from both servers:

From IP Address [destination host unreachable]

Next I ran trace route on them and got only one line that consisted of the originating server's IP.

My network configuration consists of cat5 to a standard dumb hub. When I initiate commication, I can see lights flashing on both the originating NIC and the hub.

When I run ifconfig I see that in both cases the cards transmitted but the received counter is 0. I do not have any firewall rules setup

I have tried several different hubs and cables.

Does anyone have any ideas?

 

[pcunix]

Debugging a setup like that is the most difficult task because it could be either nic, either wire, or even the hub. You've apparently eliminated wires and hubs, but either nic could be bad.

It's good to have a 3rd tcp/ip device- one of those cheap Linksys routers or an inexpensive print server or a friend's laptop (with a nic of course). That lets you find the problem quickly.

It also never hurts to have a crossover cable so that you can just patch two devices direct to each other for testing.

The best thing of course is to live near someone who already has a small working network- you bring your machines over and plug in to see if they work.

One of the things I often see is cheapo nic cards- for some reason people thing $12.00 is the right price to pay for a card- all you get for that is junk. If that's what you have, get some good cards- 3Com 3c905c's or Intel pro100's-




Tony Lawrence
SCO Unix/Linux Resources

http://pcunix.com

tony@pcunix.com

 

[DCCoolBreeze]

Thanks for the rapid response. I will try that tonight. I will try to find a crossover cable.

 

[DCCoolBreeze]

Well I tried pinging using a cross-over cable and I get the same response "desination host unreachable"; however, I can get it to work if I load Windows instead of Linux. Could there be a problem with RedHat's Linux 7.1 3C509x drivers?

 

[Nostradamus]

can you enter the output from
ifconfig -a

can you ping each nic from within the OS?
In other words... Are tcp/ip installed correctly on the two machines? /Sören

 

[DCCoolBreeze]

You know I think I pinged to NIC address successfully but I cannot remember. I will try that tonight when I get home. However, this is what I get so far.

1. ifconfig gives me lo and eth0 and the settings are
correct

2. If I use Red Hat's network configuration x-windows
app, the app show lo etho and eth1. I do not have
two ethernet cards and the card seems to be
transmitting data.

I will enter into this thread all log information this evening when I return home but could it be that the OS
believes I have two NICs? They display different interrupt values at different addresses

 

[DCCoolBreeze]

I was unable to get online last evening but I did ping the NIC card successfully and 127.0.0.1. So I can ping the network card and the loopback but I am unable to ping anything else.

 

[pcunix]

>I was unable to get online last evening but I did ping the
>NIC card successfully and 127.0.0.1. So I can ping the
>network card and the loopback but I am unable to ping
>anything else.

No, you haven't proven anything with that- a ping to the address of the card never actually goes to the card- it's immediately sent to localhost- never hits the hardware.

OK, since you say it works with Windows, that eliminates all wiring and card problems.


You say 3c509- aren't those ISA cards where you have to set the IRQ either to auto, with jumpers, or through a 3COM utility?

If they are, I'd set the irq manually (jumpers or the 3com dos utility) and specify the IRQ to Linux.

If they are PCI, ignore this.
Tony Lawrence
SCO Unix/Linux Resources

http://pcunix.com

tony@pcunix.com

 

[ifincham]

Hi,

Have you tried the 3c509.o driver rather than the 'x' version ? See -->

http://www.scyld.com/network/3c509.html

You will have to put different i/o address in your /etc/modules.conf file. Something like :

3c509 io=0x300,0x320

See also

http://support.3com.com/infodeli/inotes/techtran/4e5a_5ea.htm

Regards

 

[DCCoolBreeze]

OK. I will try that. In my case the card is on the motherboard. Also I have noticed that I get an eth1 when I do not have one. It has it's own interrupt and io address...can't figure this one out. I have cleanly installed redhat several times to try to see why this is the case.

So if I ping the NIC's ip, the NIC is not really pinged? Interesting. So are you saying then that all I am testing is the NIC driver software???.

I must say though that when I ping out to another box, the NIC card lights do show that there is traffic and when I had a hub hooked up to the system, the hub also showed traffic.

In all cases, via ifconfig, the NIC shows a value for TX and no data for RX...

 

[PcLinuxGuru]

What is the netmask set to for each computer and also make sure the IP's are on the same network.. Since there is no gateway or router here. For example

2 local computers without any connection to the internet...

1: 23.34.32.123 mask: 255.0.0.0
2: 25.43.45.67 mask: 255.255.0.0

will not work becasue they are 2 different networks...

Now something like:
1: 10.10.100.1 netmask: 255.0.0.0
2: 10.10.100.2 netmask: 255.0.0.0

will work. Best recommendation is use an IP scheme of 192.168.1.XXX replace the X's with any number from 0-255 use the default netmask which usually is 255.255.255.0 for both machine.

 

[DCCoolBreeze]

Thanks! I am still having a terrible time but now it has to do with communicating with Windows2000. This is the situation. I have setup 4 Win2K servers. One of the servers is the DHCP. All Servers can talk to each other. For simplicity I used the default DHCP set of 10.10.1.1 and an IP range of 10.0.0.1 - 10.0.0.199.

Again no problem with the communication between the NT boxes but I cannot get any communication link to or from my Linux box. Initially I tried DHCP and that did not work so I created a static ip of 10.0.0.254 with a mask of 255.0.0.0. This is what I get

dmesg displays lo, eth0 and eth1. I do not have two network cards so I do not know why eth1 shows up. I used the hardware wizard to setup the NIC. IFConfig shows that the eth0 is running and it is attached to the MAC address
eth1 does not show up in ifconfig even though it is in smesg.

If I do ping 127.0.0.1 and 10.0.0.254 success
All other pings are unsuccessful "Destination Host Unreachable"

route only shows the goes to 10.0.0.254
traceroute is the same but takes a long time to complete

I do not use a gateway or router

arp -a returns some like

{10.10.1.1} {unknown} ...

where 10.10.1.1 is my domain controller/dhcp server.

The ethernet 3x509 driver is from 3/xx/01 and I am using redhat 7.2. I know that the hardware works because I originally tested it on Windows successfully.

I really want to get Linux to work. Any help would be greatly appreciated...

 

[ifincham]

Hi,

To get rid of the rogue eth1 you should just be able to remove the associated config file :

# rm /etc/sysconfig/network-scripts/ifcfg-eth1

The redhat sysv init scripts attempt to start all interfaces in that directory, i.e. where the filename is 'ifcfg-xxxx' and xxxx is a valid interface name. After deleting that file do :

# /etc/rc.d/init.d/network retstart

A '/sbin/ifconfig' should only show your eth0, lo (and others ?) now.

If that makes no difference you can try 'mii-tool' which may or may not work on that card .

See 'man mii-tool' or

/sbin/mii-tool --help

For the sake of all the grief, it might just be easier to go out and buy a cheap pci NIC that will definitely work with linux (and windows). It could be that the linux driver is still not working correctly. Pci cards are generally much less of a problem.

Hope this helps

 

[DCCoolBreeze]

Thanks!

I got rid of eth1. Now this is the data I get:

> dmesg | grep eth
eth0: 3c5x9 at 0x220, 10baseT port, address MAC.
eth0: Setting Rx mode to 1 addresses.

> arp -a
? (10.10.1.1) at <incomplete> on eth0
? (10.0.0.1) at <incomplete> on eth0

>route
10.0.0.0 * 255.0.0.0 U 0 0 0 eth0
127.0.0.0 * 255.0.0.0 U 0 0 0 lo
default 10.255.255.254 0.0.0.0 UG 0 0 0 eth0

>traceroute 10.10.1.1
traceroute to 10.10.1.1 (10.10.1.1), 30 hops max 38 byte packets
1 10.0.0.253 (10.0.0.253) 3002.967 MS !h 2992.522 ms !H 2999.103 ms !H

>ping 10.10.1.1
from 10.0.0.253: Destination Host Unreachable
...

>ifconfig
eth0 Link encap:Ethernet HWaddr 98:AA:C0:83:FE:3F
inet addr:10.0.253 BCast:10.255.255.255 Mask:255.0.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX Packets:0 ...
TX Packets:73 ...
...
Interrupt:5 Base address:0x220

lo ...

Does this help...I hope that I do not have to get another ethernet card. This one should be. It is a 3COM 3c509