After installing ESXi, it is essential to configure its management network. The management network configuration is associated with a VMkernel interface. Think of it as a virtual network interface for VMkernel. We will learn more about these in the Chapter 3, Configuring Network Access Using vSphere Standard Switches. ESXi hypervisor runs a DHCP client, so it procures a DHCP address if there is a DHCP server on its network; however, in most cases, this is not enough. For instance, if your management network is on a VLAN, then you will need to configure a VLAN ID. Also, it is recommended to assign a static IP address for ESXi's management network.

In this recipe, we will use the Direct Console User Interface (DCUI) to achieve this.

You will need the following information to proceed with the steps:

• You will need access to the server's remote console via its IPMI interface (Dell DRAC, HPE ILO, Cisco KVM).
• The password for the root account.
• TCP/IP configuration - IP address, subnet mask, IP gateway address, VLAN ID, DNS server addresses, and hostname.

The following procedure will guide you through the steps that are required to set up the TCP/IP configuration for ESXi's management network:

1. At the main screen of ESXi, hit F2 to log in to the DCUI by supplying the root password.
2. Navigate to Configure Management Network and hit Enter:

3. The Configure Management Network screen will present you with options to select the Network Adapters, assign a VLAN ID if necessary, and configure the IPv4/IPv6 settings and DNS configuration. Each of these sections can be selected by hitting Enter and then using the onscreen instructions to select/modify/confirm the settings:

4. The Network Adapters section can be used to assign/unassign adapters to the Management Network Port Group. Use the onscreen instructions to make selections and confirm them:

5. The VLAN (optional) section is used to supply a VLAN ID for the interface. The IPv4 Configuration section is used supply an IP Address/Subnet Mask/Default Gateway:

6. The IPv6 Configuration section is used to supply IPv6 addresses. IPv6 is enabled by default. If IPv6 is not required for your environment, select the Disable IPv6 (restart required) option and hit Enter.
7. The DNS Configuration section can be used to supply primary/alternate DNS server addresses and hostnames:

8. Custom DNS Suffixes are optional if you used an FQDN as a hostname in the previous step:

9. Once you are done with all the network configuration, while on the Configure Management Network: Confirm screen, hit Esc. You will be prompted to apply the changes by restarting the management network. Hit Y to apply the settings and reboot the hosts:

10. Once the reboot is complete, you should be able to reach the ESXi host over the network. From here, the ESXi host can be managed directly using the host client or can be added to vCenter Server.

Much like the VMs that would 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 you to create 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.

Every physical network interface will have a burned-in 48-bit MAC address whose numbering is organizationally unique. This is because every vendor that makes the card will have a set of organizationally unique identifiers (OUI) assigned to them by the Institute of Electrical and Electronics Engineers (IEEE).

VMware also has a set of OUIs assigned to it, that is, 00:50:56 and 00:0C:29. Although both OUIs are used differently, they can be assigned to virtual machine NICs and the VMkernel interface.