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Re: DoS of LAN via D-Link switches

Subject: Re: DoS of LAN via D-Link switches
Date: Wed, 30 Mar 2005 09:21:14 -0500
From: Frank Bures [mailto:lisfrank@chem.toronto.edu]
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.

Reference:
http://www.oreillynet.com/pub/a/network/2001/03/30/net_2nd_lang.html

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