Easy way to check if my network card does support promiscuous mode?

[prowsej]

I want to monitor the network traffic on my network.
I thought that I would use this tool: Network Probe 2.6 at http://objectplanet.com/probe/deployment.html
In order to use it, it says that I need a network card which supports 'promiscuous mode': http://en.wikipedia.org/wiki/Promiscuous_mode
I didn't think that the network cards of any of the computers connected to my network do support promiscuous mode, but is there an easy way to check?

FYI: This is the basic question that has lead me to try this:

The situation: I am living in a house. There are five people with computers sharing internet here. It is shared via a wifi router.

The problem: Surfing the web is quite slow - pages take a long time to load - when there are multiple users using the connection but is otherwise quite fast when there is only one user.

The hypothesis: Some of the users are heavy users of file sharing programs and they are sucking up the bandwidth and slowing down the web surfing

The question: How can I track what sort of traffic users are putting over the pipes? How can I give priority to web surfing and/or slow down file sharing? How can I (dis)confirm my hypothesis that intense file sharing is to blame?

 

[Nothinman]

I've never heard of a wired NIC that didn't support promiscuous mode. If you're using a switch instead of a hub that'll be a problem, but that's not the NIC's fault.

 

[robmurphy]

If you are using a switch the promiscuous mode will not help. On a normal home switch like the one in a wifi router you can only monitor the traffic to/from your PC.

If the wifi router has an ethernet conection as its WAN interface then you could connect it via a hub, and you could then monitor the traffic on that. In that case you may need the promiscuous mode. What is the NIC on your machine?

Rob

 

[kamper]

Originally posted by: robmurphy
If the wifi router has an ethernet conection as its WAN interface then you could connect it via a hub, and you could then monitor the traffic on that.

At which point the traffic would already be nat'ed, so you can't trace it back to an internal ip. If there's a hub, it should be inserted on the LAN side.

 

[prowsej]

Thanks for the details - that must be the problem that I'm having. I guess I'd need to buy more hardware to make this work. I'll hold off on doing anything for now.