I think the real solution is training & education. Switch ports should be labeled. Those not in use s/b turned off. Your so-called network engineers should be smarter than to randomly connect switches with cables.
You might get _some_ protection if you enable STP (spanning tree protocol) in your backbone switches. Even if you don't intend to use it, it will handle some of these 'accidental' reconfigurations more gracefully and disable the erroneous paths. If the loop happens to contain an ntop probe (one of the interfaces you are listening on), you MIGHT see that everything is doubled. If the loop doesn't include the probe, all you will see is no traffic, which sort of is what you already know... so no, I agree w/ Gary, ntop won't help. -----Burton -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Sam Russo Sent: Friday, November 07, 2008 6:59 PM To: [email protected] Subject: [Ntop] detecting loopbacks on a network switch Hi All, Please excuse my ignorance if the answer to this question is easy: We've had a couple of times now in our school campus where a member of staff accidentally picks up a UTP cable and plugs it back into a switch not knowing that it is already plugged into the same switch in another port. So a loopback was created. As a result of this, our entire network goes crazy effectively rendering it useless until the loopback connection is unplugged. My aim is to be able to detect via ntop the port on the main managed switch which is exhibiting the huge excessive broadcasts which result from this loopback. From this port I can track down the location of the loopback. Last time we had this problem I was on leave and the entire campus network was down for 1 whole day. I had to come back from leave and track down where the loopback was. Any help would be appreciated. thanks sam _______________________________________________ Ntop mailing list [email protected] http://listgateway.unipi.it/mailman/listinfo/ntop _______________________________________________ Ntop mailing list [email protected] http://listgateway.unipi.it/mailman/listinfo/ntop
