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So here is my goal.

I have a number of interfaces that I want to use to playback recorded traffic. I also have a number of interfaces that I want to use the listen to the recorded traffic. I'd like to be able to programmatically map these two on the fly.

For example, I might decide one day I want monitoring interface D to monitor playback interface B.

My first thought was to use a switch with VLANs. I could put all the interfaces on the switch. I then could program the VLANs on the fly and I would put a player and a listener on the same VLAN and my problem would be solved.

Unfortunately, the switch was too smart. My monitors have to listen in promiscuous mode (the traffic isn't directed at them) and thus need to be on the same physical bus, but the switch breaks up the bus.

So I either need a switch that I can turn off switching on or a hub that has VLAN support (if I use a hub then everyone will listen to everyone and the immense amount of traffic will cause network explosion)

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up vote 8 down vote accepted

Sounds like just need a switch that does port-mirroring on any port - loads of models can do that.

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Didn't know about port mirroring. Thanks – Pace Feb 12 '10 at 21:57
Yes you are really looking for port mirroring. We use it to record VoIP calls on our network. Very easy to setup on our 3com 4500 switch. – steve.lippert Feb 12 '10 at 22:29
ironically the answer is a smart switch :P – 3dinfluence Feb 13 '10 at 2:49

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