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How to turn off promiscuous mode on a NIC?

Posted on 2004-04-27
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Last Modified: 2012-06-21
My boss is getting tons of traffic going through his NIC, and would like it to stop. I have determined that his card is most likely running in promiscuous mode and is accepting all the packets thaqt come through the network. How do I turn this off? I can't find the option anywhere.

He is using Windows 2000

Thanks.
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Question by:StickyDragon
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by:magus123
ID: 10929868
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by:PennGwyn
ID: 10931991
What tool is claiming that there are lots of packets coming through?

What does the network infrastructure look like (hubs, switches, etc)?
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by:StickyDragon
ID: 10932127
This is when you right-click the LAN connection and choose "Status" from the drop-down.
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Netscaler Common Configuration How To guides

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by:dramatix01
ID: 10934047
From the little bit of information that you have given it is very difficult to truly determine what the problem is.  It sounds like you are trying to treat the symptom and not the problem.

If you could answer some of the following questions we may be better able to help you:

1. How big is your network?
2. As PennGwyn asked, what type of network hardware are you using? (switches, hubs, etc.)
3. How old is the hardware attached to your network?

You can see where I'm going with this.  Any other information that you could offer would make this problem much easier to solve.

You may also want to stick a sniffer on your network to see if you have a chattering NIC or an employee that loves to watch or listen to streaming media while working.

Regards,
Dave...
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by:
axelt earned 30 total points
ID: 10936534
NIC's don't just turn on promiscous mode by themselves - check for viruses.

If you want to know where the traffic is coming from, download ethereal from http://www.ethereal.com/distribution/win32/
Install winpcap3.0 from the same location before installing ethereal.

When capturing - turn promiscous mode off. Stop all applications.
If you use hubs - buy switches






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Author Comment

by:StickyDragon
ID: 10941338
Definitely no viruses, we have Norton corporate, up to date definitions. Tried Ethereal. Neat program, seems that my boss is getting mostly TCP packets (whereas as I get TCP/UCP/ARP pretty evenly (And IPX for some reason, even though it isn't used). He seems to have a lot of TCP traffic coming from the Exchange server for one, and I don't for some reason. Why would this traffic be sent to one PC and not another?

1. We have about 150-200 computers
2. We have switches and hubs (all 3com rack-mount ones), but we are all connected into the same hub.... I did however move him to a switch and he had the same problem still.
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Author Comment

by:StickyDragon
ID: 10942402
Turns out it was nothing more than a driver issue with 3Com 3C920 cards! Update your drivers if you ever run into this problem.
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