On Fri, 2003-12-19 at 09:04, Chris Hobbs wrote: > Regrettably, I don't think Ethereal is going to be too helpful. We've > had the occasional problem with someone looping a minihub back into our > LAN (hooking up two ports on the minihub to two ports on the classroom > wall), and it kills the network, but doesn't show up at all on packet > sniffers. It was incredibly frustrating the first time we came across it > - now we recognize it pretty quickly and just do a class to class search > for the offending device. I forgot to mention in my previous post (the thought didn't trickle down to my fingers) that packet sniffers such as ethereal don't necessarily work well for some network debugging problems. From what I understand, the ethernet card itself will drop corrupt packets, they don't have a chance to make into the OS layer where ethereal resides. You can see that a bad packet was received (via ifconfig, for example), but you won't see the bad packet itself. As for network loops, turning on Spanning Tree protocol (STP) will fix that problem. STP breaks Macs and can cause other weirdness, however. If your switches support it, you can use "fast STP" (Cisco calls it port fast IIRC) to work around these issues while retaining most of the loop protection STP provides. -Eric
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