Hi Guys,
I have my new vm environment up and runing in in production for a little while now. All good and my users are happier. Thanks to some great help and advise from this very forum, so thank you all for that 
I have a new issue in that I need to setup a seperate self contained domain/subnet in our environment. I have setup a new vLAN 20 with the IP range 10.0.20.x/24 for this new domain. On my Layer 2 switch in that building I have blocked off the 4 ports there that I need for VLAN 20. When I assign manual IP's in that range to PC's in that room, and a printer, they all work as they should together. So far so good. On my Layer 3 switch I have my vLAN 20 setup, routing interfaces etc all as per all the other vLANs I have on the newtork.
Now my main server core - where my existing 6 production VM's live are all on vLAN10 (10.0.10.x/24). In ESXi I have my VMNetwork setup to use 3 physical Nics (Dell R710 physical host) into my Layer 3 switch. These ports are setup on the switch as untagged in vLAN10 and tagged for all other vLANs that need access to them. I have several vLANs I have setup about the place to segregate my formerly flat LAN a bit more efficiently. All is working correctly as it stands between all these vLANs.
My issue is, and what I need some guidance on: I want to add a new Windows 2008R2 VM to my environment and put it on vLAN 20 to serve those PC's and printer exclusively. I am pretty sure my issue has to do with those physical nic ports being set to untagged on vLAN 10 and setting them tagged on vLAN 20. As it is my VM cannot even ping the routing interface for that subnet on the Layer 3 switch....which is what the physical nics also plug into. So I can't ping from the VM to 10.0.20.254 (the routing interface). The rest of my network can ping 10.0.20.254 but not the VM as well. SO something is broken between the new VM and the swtich it plugs into.
Am I on the right track?? What have I overlooked, missed or done wrong?? Any help and assistance is greatly appreciated - as always