Re: DoS of LAN via D-Link switches

From: Neil Watson (bugtraq_at_watson-wilson.ca)
Date: 03/30/05

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    Date: Wed, 30 Mar 2005 09:21:14 -0500
To: bugtraq@securityfocus.com

    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 

    -- 
Neil Watson               | Gentoo Linux
Network Administrator     | Uptime 12 days
http://watson-wilson.ca   | 2.6.11.4 AMD Athlon(tm) MP 2000+ x 2
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