[c-nsp] Determining which ports have another switch attached?

Martin T m4rtntns at gmail.com
Thu Jul 21 18:42:27 EDT 2011


Phil, Gabriel,
one situation where this MAC counting does not work is when there is a
virtual machine hypervisor connected to a switch port and virtual
machines have NIC's configured to bridge mode.

IMHO counting MAC addresses in combination of checking incoming BPDU
frames on particular interface is probably the best option if CDP is
not enabled..


regards,
martin


2011/7/21 Matlock, Kenneth L <MatlockK at exempla.org>:
> 'sho spanning-tree vlan <VLAN_ID> detail | inc BPDU|Port'
>
> Look for ports with BPDU received > 0
>
> A switch coming up will probably send at least 1 BPDU before determining
> it's not the root.
>
> This of course, is assuming the switch at the other end actually talks
> STP :)
>
> Ken Matlock
> Network Analyst
> Exempla Healthcare
> (303) 467-4671
> matlockk at exempla.org
>
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Peter Pauly
> Sent: Thursday, July 21, 2011 7:37 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Determining which ports have another switch attached?
>
> Is there an easy way to determine which swtich ports have another
> switch attached to them (assume non-CDP supporting) before enabling
> bpduguard?
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
> *** Exempla Confidentiality Notice *** The information contained in this message may be privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any other dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify me immediately by replying to the message and deleting it from your computer. Thank you. *** Exempla Confidentiality Notice ***
>
>
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>



More information about the cisco-nsp mailing list