Hello,
With vSphere you can also use vShield Zones to in effect implement a firewall within the distributed virtual switch.... That can help with this.
However, in general you will want:
pNIC1 <-> vSwitch <-> vFW <-> vSwitchA <-> Company A's VMs
pNIC1 <-> vSwitch <-> vFW <-> vSwitchB <-> Company B's VMs
etc.
Note the vFW could be vShield Zones which would be better to use as with a vFW you are limited in vNICs you can use for each company.... Once you go over 3 on ESX or 7 on vSphere you need another vFW.
Best regards,
Edward L. Haletky
VMware Communities User Moderator, VMware vExpert 2009, DABCC Analyst
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Author of the books 'VMware vSphere(TM) and Virtual Infrastructure Security: Securing ESX and the Virtual Environment' available for pre-order now
'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.
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