Checking Distributed Switch PNICs for Invalid VLAN Traffic
4/26/17 Update: I changed this script so that it no longer uses the min/max VLAN numbers and instead discovers a list of valid VLANs based on the Port Groups that are defined on the VDS. It then alerts if it sees any VLANs that are not in that list. One of my customers has several physical uplinks going into their ESXi hosts, each carrying different sets of VLANs. They recently had an issue where an uplink with one set of VLANs was accidentally attached to a VDS that was configured for the other set of VLANs. This wasn't a catastrophic issue, as the VDS didn't have port groups defined for those invalid VLANs and so any traffic was dropped into the bit bucket, but it did mean that 1 of the links going into that switch was useless. After we corrected the issue, we decided that we should audit the environment to see if this problem had occurred anywhere else but not been detected. We decided that the best way to perform an initial scan of the environment would be to lever