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We have a server in a server room with 100mbit internet access.


  • supermicro C2SBX


  • Debian lenny

We use the integrated network card since 7 months. The past 1 month the server lost the internet connection repeadetly for 1-2min daily. Our internet provider changed the switch, but it didn't solve the problem. They told me that maybe the problem is the network adapter. What do you think is it the problem?

Can I somehow test it in debian?

Could you recommend a network card, which can solve the problem(we have 1pci, 1pciex8, 2pcx free slot)?


I got this image about the switch:

They told me that it's maybe QOS, because the brodcast and multi out is high.

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What's in the log files? – Bart Silverstrim Jun 23 '10 at 14:09
Which log file do you need? I don't know which can help. – user46576 Jun 23 '10 at 14:19
dmesg, system log,... – Bart Silverstrim Jun 23 '10 at 14:23
poke through /var/log until you find something that looks related to the network driver or network status. – Bart Silverstrim Jun 23 '10 at 14:25
dmesg: What means the first two number before each line? – user46576 Jun 23 '10 at 14:29

I'd just add a new card, and see if the problem persists. If it does, it's not the adapter.

Ethernet cards are cheap. You should be able to get a nice commodity gigabit card (pci) for less than 40 bucks.

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I'll weigh into this one having just experienced the same thing.

Replace your cable :)

Yes odd but the cable was replaced and the net speed is back to normal.

On cable replacement I found out that it wasn't wired properly which caused most if not all of the trouble. Some cable techs bypass the required cat5/6 specifications for wiring shorter cables and it can cause all sorts of intermittent problems.

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I have had rock solid results with Intel NICs. If you had to get a new one, I'd stick to the same and get a PCIe one.

It may be the 100Mb link that's causing you trouble.

Thinks to look at:

/var/log/kern.log (for warnings from your NIC driver)

output from 'ethtool eth0' -- this will show you what speed and settings the NIC is set at.

You can try turning off auto speed detection and hard coding the speed (100) and duplex (Full).

You could possibly have a cable problem. Swap out what's there with a new cable to test. (I hope you've already tried this).

I hope this helps.

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kern.log contains: – user46576 Jun 23 '10 at 14:32
ethtool: I can't change the cables, because it's a server hosting. – user46576 Jun 23 '10 at 14:40

Once i had similar problems when the switch was able to sync with our speed and duplex setting.
In this case you should see some errors in ifconfig dev statistics.
As already said, give a look at the linux box logs and, if possible, the switches logs.
Last but not least, try to change the cables. A lot of times they give you problems without nothing anything on the machines.

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