Security Basics: RE: how to flood the mac address table of a switch?

From: David Gillett <gillettdavid_at_fhda.edu>
Date: Wed, 3 Dec 2003 10:45:51 -0800

1. Turn off spanning tree.

2. Connect a cross-over cable between two switch ports.

3. Wait a few minutes.

WARNING: This may temporarily cripple the performance of your
network. Remember to re-enable spanning tree as soon as you're
through testing (which should shut down one of the cross-connected
ports almost immediately).

The result, though, is that every MAC address on your network
issues a broadcast packet will be "learned" on both the cross-
connected ports. If that doesn't fill up the table, your network
is probably too small to worry about this issue.

David Gillett

> -----Original Message-----
> From: Hans Müller [mailto:ndof_at_gmx.li]
> Sent: December 1, 2003 09:17
> To: security-basics_at_securityfocus.com
> Subject: how to flood the mac address table of a switch?
>
>
> How can flood the mac address table of a switch, to see that
> the security
> function of my switch work?
>
>
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Received on Dec 03 2003