[CentOS] Centos box and Cisco 3750 VLAN's

Fri May 30 19:59:41 UTC 2014
Boris Epstein <borepstein at gmail.com>

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.

Thanks in advance.

Boris.