As a part of a guest operating system customization when you deploy a virtual machine or apply a customization specification, you configure the IPv6 address settings for the guest operating system. After the customization completes, the guest operating system might not have connectivity to the IPv6 network because certain settings are not applied. The connectivity problems depend on the operating system version.

• After you customize a virtual machine thats run Red Hat Enterprise Linux, DHCPv6 addresses are no longer assigned.

  In Red Hat Enterprise Linux VMs, DHCPv6 address assignment is configured by using the IPV6INIT, IPV6_AUTOCONF, and DHCPV6C settings inside ifcfg-* files. Because of certain limitations in vSphere 6.0, you must configure these settings manually as the guest customization does not set them automatically. If the order or MAC address of the network adapters changes compared with the base virtual machine, the settings might be lost.

  Workaround:

  • Set the IPV6INIT, IPV6_AUTOCONF and DHCPV6C settings to "yes" in the ifcfg-* files of the base virtual machine.

  • Edit the ifcfg-* files according to the network adapters order or MAC address changes in the base virtual machine before you customize the VM or any of its clones.

• After you customize a virtual machine that runs Red Hat Enterprise Linux Server 4, all network adapters on the virtual machine have the same DHCPv6 address

  Version 4 of Red Hat Enterprise Linux Server might not have full IPv6 support because certain IPv6 network configurations were not available when it was released.

  Workaround: None.

• After you customize a virtual machine that runs Windows XP or Windows Server 2003, certain IPv6 capabilities are not fully functional

  On Windows XP and Windows Server 2003 guest operating systems, some IPv6 capabilities do not work after you customize the guest operating system:

  • Stateful DHCPv6 address assignment is not applied.
  • The nslookup utility is not able to resolve IPv6 DNS queries.
  • IPv6 prefix length is ignored.

  Workaround: None.

  Do not use IPv6 on Windows XP or Windows 2003 in production. See http://technet.microsoft.com/en-us/network/cc987595.aspx.

• After you customize a virtual machine that runs SUSE Linux Enterprise Server 11 SP3 or SUSE Linux Enterprise Server 12 SP0 to use a combination of static IPv4 and DHCPv6-assigned addresses, the DHCPv6 addresses are not applied.

  The customization sets the BOOTPROTO property to static for the static IPv4 configuration in the ifcfg-* files. As a result, because of design limitations related to how the property works the guest operating system does not start the DHCPv6 client.

  Workaround: Use the WIDE-DHCPv6 client to acquire DHCPv6 addresses.

• After you customize a virtual machine that runs Ubuntu Server 13.10, a static IPv6 address is not available in the ifconfig command output.

  If you run the ifconfig console command, because of design limitations in the guest operating system, the static IPv6 address is not applied to a network adapter although the address is available in the /etc/network/interfaces file.

  Workaround: None

• After you customize a virtual machine that runs Red Hat Enterprise Linux version 4 or version 5, the IPv6 address of a network adapter is not assigned if the adapter does not have an IPv4 address assigned.

  If a virtual machine network adapter does not have an IPv4 address, the IPv6 address that is assigned to the adapter in the customization specification is not applied because of failures in the networking scripts of the guest operating system.

  Workaround: To assign an IPv6 address to a virtual machine network adapter, enable the IPv4 address on the adapter that is static or assigned by a DHCPv4 server.

• After you customize a virtual machine that runs SUSE Linux Enterprise Server 10 SP4, the DHCPv6 client does not start.

  SUSE Linux Enterprise Server version 10 SP4 might not have full IPv6 support because certain IPv6 network configurations were not available when it was released.

  Workaround: Use the WIDE-DHCPv6 client to acquire a DHCPv6-assigned address.

• After you customize a virtual machine that runs Ubuntu, if DHCPv4 is not available in the network, the nslookup utility cannot resolve host names that are mapped to IPv6 addresses.

  On an Ubuntu virtual machine that has DHCPv4 and DHCPv6 enabled, the nslookup utility does not resolve host names that are mapped to IPv6 addresses on the DNS server if a DHCPv4 server is not available in the network.

  Workaround: Configure a DHCPv4 server in the network.

• After you customize a virtual machine that runs Windows or Ubuntu with stateful DHCPv6, the DHCPv6-assigned prefix length is always set to 128 bits.

  The prefix length on these guest operating systems is always set to 128 bits if you enable stateful DHCPv6 regardless of the actual prefix length in the router advertisement message.

  Workaround: None.

• After you customize a virtual machine that runs Windows Vista or later, the IPv6 addresses of a network adapter is not assigned if address assignment is DHCPv6

  The BROADCAST flag is enabled by default in the DHCPv6 discovery packets that Windows Vista or later sends to request an IPv6 address for the network adapter. The router or DHCPv6 server might not be able to handle this flag and as a result the network adapter of the virtual machine might not receive an IPv6 address.

  Workaround: See Microsoft knowledge based article 928233 at http://support.microsoft.com/kb/928233.