The VMkernel network interface (vmk)

Much like the virtual machines that run on the ESXi hosts, the vmkernel would also need to interface with the network for a variety of purposes. These interfaces act as network node points for the vmkernel. The very first vmkernel interface - vmk0 is created during the installation of ESXi. This interface is the management interface for the ESXi host. VMware allows creating a maximum of 256 (vmk0 - vmk255) vmkernel interfaces on an ESXi host. The use cases include interfaces for management traffic, VMotion traffic, FT traffic, Virtual SAN traffic, iSCSI, and NAS interfaces. Since each interface is a network node point, it will need an IP configuration and a MAC address. The first vmkernel interface (vmk0) will procure the MAC address of the physical NIC it is connected to. The remaining interfaces pick up the VMware OUI MAC address generated by the ESXi host. We will learn more about how VMware handles the MAC address in the next section.