<<< Date Index >>>     <<< Thread Index >>>

Re: DoS of LAN via D-Link switches



Neil Watson wrote:
From: Frank Bures [mailto:lisfrank@xxxxxxxxxxxxxxxx]
Sent: Tuesday, March 29, 2005 4:41 AM
In my opinion, a switch should be immune to this admittedly insane
manipulation.  Otherwise, one can DoS the entire network just
by shorting
two RJ-45 network outlets in one's office together.

I believe what you are describing is officially called a bridge loop. A
bridge loop occurs when a switch, or stack of switches are plugged into
themselves. The result is that the switches report the same MAC address
at multiple ports.  The solution to this is called Spanning Tree
Protocol.  STP is a set of algorithms that help switches remove
redundant MAC entries.

And it can be particularly hard to find. XO Communication's Irvine Data Center has been struggling with what they believe to be the same kind of problem for the last couple of days (and I've been struggling with connectivity).