[CentOS] Centos box and Cisco 3750 VLAN's

Fri May 30 20:11:46 UTC 2014
Antonio da Silva Martins Junior <asmartins at uem.br>

----- "Boris Epstein" <borepstein at gmail.com> escreveu:

> De: "Boris Epstein" <borepstein at gmail.com>
> Para: "CentOS mailing list" <centos at centos.org>
> Enviadas: Sexta-feira, 30 de Maio de 2014 16:59:41 (GMT-0300) Auto-Detected
> Assunto: [CentOS] Centos box and Cisco 3750 VLAN's
>
> Hello all,
> 
> I have a CentOS box that has a NIC (eth0) on which I defined 4 VLAN's
> (counting the NIC itself): eth0, eth0.1, eth0.2 and eht0.3. Initially
> the Cisco switch was not partitioned into VLAN's which means that the only
> VLAN running on it was the default one (VLAN 1).
> 
> I have then played with VLAN's a bit on the switch and at this point
> have two: VLAN 1 (which is default and can not be deleted) and VLAN 3. The
> CentOS box is plugged into a trunk port on VLAN 3 which by virtue of
> being a trunk should belong to all VLANs. However, this does not seem to
> work as expected.
> 
> What I get is the following:
> 
> 1) eht0 does not come up at all.
> 
> ifup eth0
> Device eth0 does not seem to be present, delaying initialization
> 
> 2) eth0.3 comes up fine.
> 
> 3) Other VLAN's do not come up. No error messages, just never show
> up.
> 
> Any insight into this would be most welcome. Primarily, I fail to
> understand why all those VLAN's came up on VLAN 1 and why now even
> VLAN 1 does not come up - even though the trunk port the device is plugged
> into is supposed to be a member of all VLAN's.

Hi Boris,

   Well, can you send to us the result of the "show run interface" on the 
switch interface? Maybe seeing the switch configuration we can help :D

   On the VLAN1 matter, you cannot "disabled" it. But, you can shut it down,
and can restrict the access to it on that port. If it was needed. :D

   Thanks,

          Antonio.

-- 
Antonio da Silva Martins Jr. 
Analista de Suporte
NPD - Núcleo de Processamento de Dados
UEM - Universidade Estadual de Maringá
email: asmartins at uem.br 
fone: +55 (44) 3011-4015 / 3011-4411
inoc-dba: 263076*100                     

     "Real Programmers don’t need comments — the code is obvious."

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