VLANs are supported with XenServer. Switch ports configured as 802.1Q VLAN trunk ports can be used with the Citrix Hypervisor VLAN features to connect guest virtual network interfaces (VIFs) to specific VLANs. In this case, the Citrix Hypervisor server performs the VLAN tagging/untagging functions for the guest, which is unaware of any VLAN configuration.

Citrix Hypervisor VLANs are represented by additional PIF objects representing VLAN interfaces corresponding to a specified VLAN tag. You can connect Citrix Hypervisor networks to the PIF representing the physical NIC to see all traffic on the NIC. Alternatively, connect networks to a PIF representing a VLAN to see only the traffic with the specified VLAN tag. You can also connect a network such that it only sees the native VLAN traffic, by attaching it to VLAN 0.

Please refer to https://tinyurl.com/y4wqtsld