VMware ESX Server 2.0Features | Documentation | Knowledge Base | Discussion ForumsFor security reasons, guest operating systems are not normally allowed to set their virtual Ethernet adapters to use promiscuous mode. In some circumstances, you may need to use the virtual Ethernet adapters in promiscuous mode. To enable this use, you must set the PromiscuousAllowed configuration variable to yes. To do so, follow these steps.
You may want to allow only some adapters on a particular network to use promiscuous mode. In that case, you can selectively disable promiscuous mode based on the MAC address of the virtual machine's Ethernet adapter. To do so, follow these steps.
In many ESX Server configurations, there is a clear distinction between networking resources used by the virtual machines and those used by the service console. This may be important for security reasons, for example — isolating the management network from the network used by applications in the virtual machines. However, there may be times when you want to share resources, including physical network adapters and virtual networks. This technical note provides instructions on sharing in both directions — making the virtual machines' resources available to the service console and allowing virtual machines to share the network adapter used by the service console. This sharing is made possible by the vmxnet_console driver, which is installed with the service console. Caution: We recommend that only advanced users make these configuration changes. The steps below are easier for someone who is familiar with administering a Linux system. Note: If you accidentally bring down the local loopback interface while you are reconfiguring network devices, the VMware Management Interface does not function properly. To bring it back up, use the command ifconfig lo up. All network adapters used by virtual machines (that is, assigned to the VMkernel) and virtual networks can be made accessible to the service console. Virtual networks — identified as vmnet_<n> on the Edit Configuration page of the VMware Management Interface — provide high-speed connections among virtual machines on the same physical server. To give the service console access to VMkernel network adapters and virtual networks, you must install the vmxnet_console module. When you install it, you provide a list of VMkernel network adapters and virtual networks that the vmxnet_console module should attach to. For example, if the VMkernel had an adapter named vmnic1 and a virtual network named vmnet_0 and you wanted to provide access to them from the service console, you would use the following command to install the vmxnet_console module. insmod vmxnet_console devName=vmnic1;vmnet_0 The devName parameter is a comma-separated list of names of VMkernel network adapters and virtual networks. When you install the module, it adds the appropriate number of eth<n> devices on the service console in the order that you list the VMkernel network adapter and virtual network names after the devName parameter. In the example above, if the service console already had a network adapter named eth0, when you load vmxnet_console with vmnic1 and vmnet_0; vmnic1 is seen as eth1 on the service console and vmnet_0 is seen as eth2. Once the eth<n> devices are created on the service console, you can bring the interfaces up in the normal manner. For example, if you want the service console to use IP address 10.2.0.4 for the network accessed via the vmnic1 adapter, use the following command: ifconfig eth1 up 10.2.0.4 If you want an easy way to see which eth<n> devices are added by the insmod command, you can add the tagName parameter to the insmod command, as shown in this example: insmod vmxnet_console devName=vmnic1;vmnet0 tagName=<tag> In this case the vmxnet_console module adds the names of each of the eth<n> devices that it created to /var/log/messages. Each message begins with the string <tag>. To figure out the names of the devices that were added, use this command: grep <tag> /var/log/messages There are two ways you can configure the service console to start VMkernel network adapters when the service console boots. The simpler case involves sharing a network adapter other than eth0. Sharing eth0 is more complicated and is described later. Continuing with the example from the previous section, you can append the following lines to /etc/rc.d/rc.local:
insmod vmxnet_console devName=vmnic1,vmnet0 Another method is to set up the files /etc/sysconfig/network-scripts/ifcfg-eth1 and /etc/sysconfig/network-scripts/ifcfg-eth2 with the appropriate network information. And be sure the ONBOOT= line is ONBOOT=yes. The ifcfg-eth1 file for this example would be
DEVICE=eth1 In this case, the lines you add to /etc/rc.d/rc.local would be:
insmod vmxnet_console devName=vmnic1;vmnet0 Caution: If you intend to share the adapter that is eth0 on the service console, be careful as you implement the following steps. In order to configure ESX Server initially, you need to have a network connection. Once the initial configuration is set, you make several changes. At one point in the process, there is no network connection to the service console, and you must work directly at the server. When you first install and configure ESX Server, the VMkernel is not loaded, so the service console needs to control the network adapter that is eth0. When you configure ESX Server, assign the adapter that is eth0 to the service console. Once you have completely configured ESX Server properly and rebooted the machine, the VMkernel is loaded. At that point, you need to take the following steps:
NIC teaming enables you to group logically together physical network interface cards (NICs) to form one single virtual teaming device, called a bond. By binding all these NICs together, you can ensure network connectivity to the server and improve network performance. This feature also provides traffic load balancing and redundant NIC operation if a network connection fails. To use NIC teaming, you must have multiple physical NICs assigned to NIC teaming. You can then combine your virtual NICs into a team, called a bond. Each bond comprises at least one, up to ten virtual NICs. You may create up to ten bonds, from bond0 through bond9, for each ESX Server. You create a bond by adding virtual NICs to the bond. There are several constraints regarding virtual NICs and bonds:
Once a virtual NIC is assigned to a bond, this virtual NIC becomes unavailable. You will no longer see this virtual NIC in the drop-down list of Ethernet adapters in the virtual machine configuration page. You can remove a virtual NIC from a bond only when the bond is not in use.
If, while booting your virtual machine, you see an error message stating that the Ethernet device cannot be detected, then check the following:
Make the appropriate change(s), then reboot your virtual machine to see if the error message persists.
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