During the VM configuration, you must select the adapter type and the network it will connect to. Depending on the VM compatibility and the guest OS, the supported NIC types are the following:

• E1000E: This is the default adapter for Windows 8 and Windows Server 2012. It emulates the Intel 82574 Gigabit Ethernet NIC.
• E1000: This driver is available in most newer guest OSes and emulates the Intel 82545EM Gigabit Ethernet NIC.
• Flexible: This identifies itself as a Vlance adapter, an emulated version of the AMD 79C970 PCnet32 LANCE NIC. Most 32-bit guest OSes have the driver for this NIC type. When installing Virtual Machine Tools, the adapter changes to the higher-performance VMXNET adapter.

• VMXNET: This is optimized for VM performance. To provide the driver, it requires Virtual Machine Tools to be installed.
• VMXNET 2 (Enhanced): Based on the VMXNET adapter, this provides high-performance features, such as jumbo frames and hardware offloads. A limited set of guest OSes support it.
• VMXNET 3: This offers all the features available in VMXNET 2 and it's a paravirtualized NIC designed for performance. Multiqueue support (known as RSS in Windows), IPv6 offloads, and MSI/MSI-X interrupt delivery are some of the additional features offered by this adapter. It requires VM hardware version 7 or later, and a limited set of guest OSes support it.

By default, the MAC address is automatically generated from the vCenter Server MAC address pool, but you can set a manual MAC address if you need to.