Understanding Virtual networking Concepts
VMware provides a very useful and varied networking infrastructure that can be used for a variety of testing and hosting purposes. In these following articles we will explore the world of VMware Networking infrastructure and how we can leverage it while designing/ building Virtual Machines for VMware Workstation.
Understanding Common Networking Configurations
You can configure bridged networking, NAT, and host-only networking for virtual machines. You can also use the virtual networking components to create sophisticated custom virtual networks.
1. Bridged Networking
Bridged networking connects a virtual machine to a network by using the network adapter on the host system. If the host system is on a network, bridged networking is often the easiest way to give the virtual machine access to that network.
When you install Workstation on a Windows or Linux host system, a bridged network (VMnet0) is set up for you.
2. NAT Networking
With NAT, a virtual machine does not have its own IP address on the external network. Instead, a separate private network is set up on the host system. In the default configuration, a virtual machine gets an address on this private network from the virtual DHCP server. The virtual machine and the host system share a single network identity that is not visible on the external network.
When you install Workstation on a Windows or Linux host system, a NAT network (VMnet8) is set up for you. When you use the New Virtual Machine wizard to create a new virtual machine and select the typical configuration type, the wizard configures the virtual machine to use the default NAT network.
You can have only one NAT network.
3. Host-Only Networking
Host-only networking creates a network that is completely contained within the host computer. Host-only networking provides a network connection between the virtual machine and the host system by using a virtual network adapter that is visible on the host operating system.
When you install Workstation on a Windows or Linux host system, a host-only network (VMnet1) is set up for you.
4. Custom Networking Configurations
With the Workstation virtual networking components, you can create sophisticated virtual networks. The virtual networks can be connected to one or more external networks, or they can run entirely on the host system.
You can use the virtual network editor to configure multiple network cards in the host system and create multiple virtual networks.
Understanding Virtual Networking Components
The virtual networking components in Workstation include virtual switches, virtual network adapters, the virtual DHCP server, and the NAT device.
Like a physical switch, a virtual switch connects networking components together. Virtual switches, which are also referred to as virtual networks, are named VMnet0, VMnet1, VMnet2, and so on. A few virtual switches are mapped to specific networks by default.
Default Virtual Network Switches
Workstation creates virtual switches as needed, up to 10 virtual switches on a Windows host system and up to 255 virtual switches on a Linux host system.
You can connect an unlimited number of virtual network devices to a virtual switch on a Windows host system and up to 32 virtual network devices to a virtual switch on a Linux host system.
On Linux host systems, the virtual switch names are in all lowercase letters, for example, vmnet0.
1. Virtual Network Adapters
When you use the New Virtual Machine wizard to create a new virtual machine, the wizard creates a virtual network adapter for the virtual machine. The virtual network adapter appears in the guest operating system as an AMD PCNET PCI adapter or Intel Pro/1000 MT Server Adapter. In Windows Vista and Windows 7 guest operating systems, it is an Intel Pro/1000 MT Server Adapter.
Workstation 6.0 and later virtual machines can have up to 10 virtual network adapters. Workstation 4 or 5.x virtual machines are limited to three virtual network adapters.
2. Virtual DHCP Server
The virtual Dynamic Host Configuration Protocol (DHCP) server provides IP addresses to virtual machines in configurations that are not bridged to an external network.
For example, the virtual DHCP server assigns IP addresses to virtual machines in host-only and NAT configurations.
3. NAT Device
In a NAT configuration, the NAT device passes network data between one or more virtual machines and the external network, identifies incoming data packets intended for each virtual machine, and sends them to the correct destination.