[CentOS] OT - odd behavior of Cisco switch

[Giles Coochey]

On 06/02/2013 18:34, m.roth at 5-cent.us wrote:
> Les Mikesell wrote:
>> On Wed, Feb 6, 2013 at 11:19 AM, SilverTip257 <silvertip257 at gmail.com>
>> wrote:
>>> If one of your hosts intermittently loses connectivity, the switch will
>>> broadcast that traffic to all ports because it can't find the host's MAC
>>> address.
>>>
>>> (And what Les said about the switch broadcasting traffic until it learns
>>> MAC addresses.)
>> Some spanning tree events will force the switch to re-learn MACs too.
> I should have mentioned this switch is *only* in use on our subnet, though
> of course we go through it to go Out There, there are gov't firewalls
> outside of it. All the traffic is only on our subnet, in this case, and
> the weirdness was intermittent.
>
> At the time, there were two heavy users (me, doing an offline backup, from
> one room to another, the latter with the server being hit by me in it, and
> at that switch, and another user doing heave scientific computing). That
> is, of course, in addition to all the other normal traffic from dozens of
> other servers.
>
> Btw, he's not seeing it today, but I'm not running any more backups just
> now....
>
>
You may have some trunking issues if you use VLANs, inter-operate these 
switches with non-Cisco equipment and have left every port on the switch 
in the default VLAN1.

Have you actually configured the switch, or did you just plug it in and 
get running?

-- 
Regards,

Giles Coochey, CCNA, CCNAS
NetSecSpec Ltd
+44 (0) 7983 877438
http://www.coochey.net
http://www.netsecspec.co.uk
giles at coochey.net