[c-nsp] Identifying device(s) connected to cisco L2-only switch

[Rakesh Hegde]

As Dan said , I would also use port security to get the source mac .You can
also enable bpdguard on the switch port just to make sure that you are not
receiving any BPDUs.If the switch port is a trunk you may want to enable
port security for all vlans allowed on the trunk.
-Rakesh.

On Sat, Nov 1, 2008 at 4:07 PM, Dan <method at b.astral.ro> wrote:

> Hi ,
>
> I would say set on port :
>
> port-security with mac-address sticky - > first frame must have a src
> mac-address ( or if there will be many you will have logs )
> bpduguard enable -> if it's a switch ( with spanning-tree enabled ) you
> will have the port on err-disable
> Any cdp info ?
>
> Dan
>
> Dale Shaw wrote:
>
>> Hi all,
>>
>> Here's the scenario:
>>
>> - L2 switchport in cat3750 "up/up"
>> - No MAC learnt on the interface ("sh mac-addr int gi1/0/4" shows no
>> dynamic MAC address)
>> - Attached device not necessarily configured with an IP in the correct
>> VLAN (mismatched with switchport) - endpoint IP configuration unknown
>>
>> I haven't really given this much consideration, but does anyone know
>> of any tricks, ideally executed _from_ the switch, to encourage the
>> attached device to spit back a frame? Essentially I want/need to
>> figure out what's attached. Even knowing the MAC vendor would help.
>>
>> Other suggestions are welcome. I guess I could try things like a
>> broadcast ping from a host in the same VLAN, make the port a trunk and
>> madly ping sweep, but something more elegant would be nice.
>>
>> A physical inspection, in this case, is not possible.
>>
>> cheers,
>> Dale
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