[CentOS] VLAN issue

Sat Jan 24 23:53:51 UTC 2015
SilverTip257 <silvertip257 at gmail.com>

Andrew and Dennis are spot on.
Their conclusions about your server being connected to an access port and
not a trunk port would be my conclusion as well.

On Sat, Jan 24, 2015 at 9:11 AM, Dennis Jacobfeuerborn <
dennisml at conversis.de> wrote:

> Hi Boris,
> what I'd like to know is the actual VLAN configuration of the switch
> port (link-type and tagged and untagged VLANs). When I look at the
> switchport coniguration here I get (among other things):
> ...
>  Port link-type: trunk
>   Tagged   VLAN ID : 8, 1624
>   Untagged VLAN ID : 10
> ...
> Here is my suspicion:
> Your ports have an access link-type with an untagged VLAN ID of 48. That
> would explain why the moment you configure an IP from that VLAN on eth0
> you get connectivity because then the packets the Linux box sends are
> untagged as the switch would expect them to be. If you only put an
> address on eth0.48 then the packets get tagged by Linux but if the
> switch port is not configured to receive the packets for VLAN 48 as
> tagged then it will simply drop these packets and you will not get
> connectivity.

Additionally, the switch should gripe about 802.1q BPDUs.
Check the in-memory system log (or syslog server if you have configured

show logging | i 1Q

Received 802.1Q BPDU on non trunk FastEthernet0/2 on vlan 100.

> So getting the actual VLAN config of the switch port would help to
> determine if the switch actually expects to receive the packets the way
> you send them from the Linux box.
Let's see the config for the switch port your server is connected to.

//  SilverTip257  //