NetApp devices support the industry standard 802.1q format, but they require all VLAN’s to be tagged. I was helping a co-worker to configure a Cisco switch to support a NetApp Filer for multiple VLAN’s (VLAN’s 1, 2, and 3). Network connectivity was working for VLAN’s 2 and 3, but was not working for VLAN 1. Cisco does not add an 802.1q VLAN tag to traffic in the “native” VLAN (VLAN 1 by default on trunk interfaces). There are two options to correct this situation; tag VLAN 1 traffic or set the native (un-tagged) VLAN to a VLAN that doesn’t need to be used on the filer. There are a variety of reasons not to use VLAN 1, but simply tagging the traffic allowed all three networks to become visible.
Option 1 (tag the native VLAN)-
Switch(config)#vlan dot1q tag native
Option 2 (make the native VLAN something you don’t intend to use on the filer)-
Switch(config-if)#switchport trunk native vlan XXX (where XXX is an unused VLAN number)