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I am building a CCIE lab where I will use GNS3 to map virtual router interfaces to physical NIC interfaces which connect to physical switches. I want to build this in an ESXi5 Guest running Win 7. My ESXi5 host has 3x Sun X1034A cards which I had to write custom drivers for to get working with ESXi. ESXi detects all 12 ports across my 3 cards with no problems.

It seems to achieve the physical connectivity that I need, I must create a separate vSwitch for each NIC port. So I end up with 12 vSwitches with 1 NIC interface in each. I then go to my Guest and start adding the Ethernet Adapters, tying them to each vSwitch one at a time. I reach 10 adapters and suddenly I cant add anymore!

Is there a way around the 10 limit? I tried manually editing my VMX file, adding the NICs but they don't show up in vSphere. Or is there a better way to set this up and I am doing it wrong?

Any help is greatly appreciated. Anyone interested in building your own custom drivers for ESXi should check out trickstarter's tread on


EDIT: Thanks for your responses. Perhaps there is a config trick to accomplish what I am trying to do? Any ESX masters in the house? ;)

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All the documentation I've read states that 10 vNIC's are the maximum per VM. I don't see how you could get around that. – joeqwerty Mar 27 '13 at 16:13
up vote 9 down vote accepted

There is a limit of 10 NIC's enforced in vSphere:

XenServer supports 7:

Hyper-V 2008 R2 support 12 (But caveated):

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could you post the exact verbiage from the pdf? I see Max Virtual Nics as 10^7, – D3l_Gato Mar 27 '13 at 16:13
Hah! That'd be nice. The 7 is a footnote: 7. Any combination of supported virtual NICs. – MikeyB Mar 27 '13 at 16:16
I need to get sleep lol :) Thanks Mikey. No one has found a way around this? – D3l_Gato Mar 27 '13 at 16:17
Maybe try a different virtualization product. – SpacemanSpiff Mar 27 '13 at 16:26
@D3l_Gato Hehe - as a CCIE candidate you know full well that the right answer isn't always the one that we want! – Dan Mar 27 '13 at 16:40

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