As far as I know this is red hat linux based, correct? Try to add the vlan on the interface with the command
vconfig
Usage: add [interface-name] [vlan_id]
rem [vlan-name]
set_flag [interface-name] [flag-num] [0 | 1]
set_egress_map [vlan-name] [skb_priority] [vlan_qos]
set_ingress_map [vlan-name] [skb_priority] [vlan_qos]
set_name_type [name-type]
* The [interface-name] is the name of the ethernet card that hosts
the VLAN you are talking about.
* The vlan_id is the identifier (0-4095) of the VLAN you are operating on.
* skb_priority is the priority in the socket buffer (sk_buff).
* vlan_qos is the 3 bit priority in the VLAN header
* name-type: VLAN_PLUS_VID (vlan0005), VLAN_PLUS_VID_NO_PAD (vlan5),
DEV_PLUS_VID (eth0.0005), DEV_PLUS_VID_NO_PAD (eth0.5)
* bind-type: PER_DEVICE # Allows vlan 5 on eth0 and eth1 to be unique.
PER_KERNEL # Forces vlan 5 to be unique across all devices.
* FLAGS: 1 REORDER_HDR When this is set, the VLAN device will move the
ethernet header around to make it look exactly like a real
ethernet device. This may help programs such as DHCPd which
read the raw ethernet packet and make assumptions about the
location of bytes. If you don't need it, don't turn it on, because
there will be at least a small performance degradation. Default
is OFF.