6.5.1

Table Of Contents
To switch from range- or prefixed-based allocation back to VMware OUI allocation, or between range- and
prefixed-based allocation, edit the vpxd.cfg file manually. See Set or Change Allocation Type.
Note You should use prefix-based MAC address allocation in vCenter Server 5.1 and ESXi 5.1 hosts,
and later.
If a vCenter Server 5.1 instance manages hosts running ESXi versions earlier than ESXi 5.1, use
VMware OUI prefix-based MAC address allocation. Virtual machines assigned non VMware OUI prefixed
MAC addresses fail to power on on the pre-5.1 hosts. These hosts explicitly check if an assigned MAC
address uses the VMware OUI 00:50:56 prefix.
Procedure
1 In the vSphere Web Client, navigate to a vCenter Server instance.
2 On the Configure tab, expand Settings and select Advanced Settings.
3 Click Edit.
4 Add or edit parameters for the target allocation type.
Use only one allocation type.
n
Change to prefix-based allocation.
Key Example Value
config.vpxd.macAllocScheme.prefixScheme.prefix
005026
config.vpxd.macAllocScheme.prefixScheme.prefixLength
23
prefix and prefixLength determine the range of MAC address prefixes that newly added
vNICs have. prefix is the starting OUI of MAC addresses related to the vCenter Server
instance, and prefixLength determines the length of the prefix in bits.
For example, the settings from the table result in VM NIC MAC addresses starting with 00:50:26
or 00:50:27.
n
Change to range-based allocation.
Key Example Value
config.vpxd.macAllocScheme.rangeScheme.range[X].begin
005067000000
config.vpxd.macAllocScheme.rangeScheme.range[X].end
005067ffffff
X in range[X] stands for the range sequence number. For example, 0 in range[0] represents
the allocation settings of the first range for MAC address allocation.
5 Click OK.
Set or Change Allocation Type
If you are changing from range- or prefixed-based allocation to the VMware OUI allocation, you must set
the allocation type in the vpxd.cfd file and restart the vCenter Server.
vSphere Networking
VMware, Inc. 205