Guest OS Customization changes VM's IPv6 Address

Products

• VMware vCenter Server

Issue/Introduction

When creating a VM using custom guest OS customization, the VM creates with an IPv6 assigned but after guest OS customization completes, the IPv6 address changes.

Environment

vCenter Server 8.X

Windows OS

Cause

This is an issue related to the functionality of Microsoft Windows sysprep. It is not caused by VMware by Broadcom products which are reliant on sysprep behavior for Windows VMs.

There are three potential scenarios regarding this IPv6 issue:

Scenario A: The MAC Address and NIC do not change. Because the DHCPv6 scope for the VLAN does not change, the IPv6 also does not change.

Scenario B: Changing the VLAN causes the NIC to be recreated or a new MAC Address is assigned. Because a new virtual NIC is created with a different MAC address, the DUID and IPv6 will change.

Scenario C: The VLAN is changed to a different DHCPv6 scope. This can result in the IPv6 changing even if the MAC address does not change.

Resolution

Ensure that the new VM does not get a different DHCP6 scope, new NIC or new MAC address assigned after guest OS customization completes.