vNetwork : document-vlans

Information

If you are using VLAN tagging on a vSwitch, these need to correspond to the ID's on external VLAN-aware upstream switches if any. If VLAN ID's are not tracked completely, mistaken re-use of ID's could allow for traffic to be allowed between inappropriate physical and virtual machines. Similarly, wrong or missing VLAN ID's may lead to traffic not passing between appropriate physical and virtual machines.

See Also

https://www.vmware.com/files/xls/hardeningguide-vsphere5-5-ga-released.xlsx