network cards issue.

[john D_3]

Hi I have Linux 7.x version installed on intel based server. I have three network cards on it.

I am facing a problem if I leave the machine on for 2 - 3 hours it loose the connectivity. I mean nobody would be able to ping or to connect with this machine by any ways.

I checked both cards are up, ip addresses are properly bound, there is no screen saver or power management option is running.

Also at that time I am not able to use webmail also.

However if I do ping locally to these cards, suddenly they start working. This is a behaviour of all the three cards.

Can some help me out

[Huc_1]

If something gets changed surely there must be a trace somewhere?.
Have you had a look in /var/log/messages, well that is also in all of the files in the /var/log .. perhaps this could get you on the trace of what is wrong .... also dmesg may help you here ... tell us about you finding so we can help futher.


J-P

[Steven E. Protter]

Common issue:

You've choosen an ip address thats a duplicate of another ip address somewhere else on the network.

It could be some windows workstation or wheatever and when it goes on, you lose network connectivity. There should be a message about this in /var/log/messages.

Then it happens, from a workstation, do a traceroute (tracert) from windows. Is the route taken the expected route.

SEP

[Mobeen_1]

Mehmood,
I totally agree with Stepen in his suggestion. From what you have explained it defintely looks like this is a typical symptom of duplicate IP.

I would suggest that you rule this out before proceeding with any other suggestions that are thrown at you or that come to your mind

regards
Mobeen

[john D_3]

Hi I checked /var/adm/messages file but I did not see any duplicate ip error. However there are some errors like;

eth1 NIC Link is Up 10 Mbps Half Duplex

Is there any possbility to change it full duplex and change the speed to 100mbps?? and it will resolve the problem.

Thanks

[Govind_3]

Hi Mehmood,
1)Could you give the output of ifconfig -a for this server?
2)Also do you see any messages for "NIC Link DOWN"?
3)when you say Linux 7.x do you mean redhat or some other flavour?
-Regards
Govind

[Johannes Krackowizer_1]

hi mehmood,

what type of card are you using. some drivers allow some parameters while loading.
For example Intel e1000:
modprobe e1000 duplex=2 Speed=1000
means load driver for e1000 based card with full duplex and 1000MBps

Have a look at
/Documentation/networking/
for explanation of parameters for all supported nic's.

[Ross Minkov]

Mehmood,

To disable autonegotiation, and force the MII to 100baseTx-FD use -F option to mii-tool. This utility checks or sets the status of a network interface's Media Independent Interface (MII) unit. Most fast ethernet adapters use an MII to autonegotiate link speed and duplex setting.

If you want to check current settings on all network interfaces just type:
/sbin/mii-tool

To disable autonegotiation, and force the MII to 100baseTx-FD on eth1 use:
/sbin/mii-tool -F 100baseTx-FD eth1

To make these settings persist a reboot add them in /etc/rc.d/rc.local

Add something like this to the end of it:

#Force 100baseTx Full Duplex for eth0 & eth1
/sbin/mii-tool -F 100baseTx-FD eth0
/sbin/mii-tool -F 100baseTx-FD eth1


HTH,
Ross

[Ross Minkov]

Forgot to mention that you should make sure that the switch ports have auto-negotiate turned off and set to 100FD first. The goal is always to match the settings on the ends of the cable (system end and switch end).

[Johannes Krackowizer_1]

did you check the cabeling?
does the other end point (switch, hub, router) support 100MBps Full Duplex?
Could it be that the port on the switch is set to 10MBps Half Duplex?
Did you use the nic before in another computer? Did you use a DOS tool to configure the nic to some settings?