HowTo: Add 4th NIC to VMware Workstation virtual machines

Sometimes you could need to setup particular network scenarios in virtual machines, where routers or firewalls need 4 network interface cards.
While the new VMware Server 1.0 supports 4 of them, VMware Workstation 5.5.1 (and older) does not.

The following how-to details how to add the 4th NIC to new Workstation virtual machines or existing ones.

1. Create a new virtual machine with 3 NICs as usual and power it on (even if it has no operating system inside). After few seconds you can power it off and shut down Workstation.
If you want to add 4th NIC to an existing virtual machine just jump to step 2.

2. Go to the directory where the virtual machine is stored, open the .vmx file with Notepad or any other editor tool and add following 6 lines on bottom:

ethernet3.present = “TRUE”
ethernet3.addressType = “generated”
ethernet3.generatedAddress = “00:0c:29:08:35:c3” (this will change at next boot)
ethernet3.generatedAddressOffset = “30”
ethernet3.connectionType = “bridged” (replace with anything you like)
ethernet3.vnet = “VMnet4” (replace with anything you like)

3. Save the file and power on your virtual machine.

Note: This trick will not work to add 5th network card on Workstation 5.5.1 or Server 1.0, so don’t waste time trying.
This depends on amount of PCI slot VMware defined for its virtual computer (here more details).

Remember that 4th NIC in VMware Workstation virtual machines is unsupported and effects on virtual network performances and reliability are unpredictable.
Since VMware Server already supports it we can assume the formal limit will be extended in upcoming Workstation 6.0.