Networking with VMware
Virtual machines in VMware are networked in a variety of ways, as displayed previously in Figure 5. Those choices are Bridged, NAT, Host-Only, or Do Not Use Networking. Bridged networking is the most common option, which I used for both my virtual machines.
In this option, the Host NIC is shared with the guest machines, with a virtual NIC created for each guest machine. The VMware software creates a couple of virtual network adapters, which will show up in the network connections of the host machine.
The virtual NIC(s) are bridged to a virtual switch created within VMware. The physical NIC is also bridged to this virtual switch. This "bridge" enables the virtual NIC to connect to the same network as the physical NIC. The virtual machine can be a DHCP client and gain an IP from a DHCP server, just as the physical NIC.
Alternatively, a static IP can be assigned to the virtual machine via the network configuration of the virtual machine's OS. Both scenarios enable a virtual machine to appear as a real physical machine to all other devices on the network. Figure 11 is taken from VMware Server?s manual, and shows the bridged networking layout.
Figure 11: VMware bridged network diagram
I use the 192.168.3.0 /24 network for my LAN, with my XP Pro machine's IP address being 192.168.3.15. By going into my router, I was able to determine that the Linux virtual machine was assigned 192.168.3.16 and the FreeNAS virtual machine was assigned 192.168.3.17.
From a network perspective, both of these virtual machines are completely independent of the XP Pro Host, with their own IP addresses. Indeed, I can access and ping all three machines simultaneously, even though they are sharing the same physical NIC.
Another VMware networking option is NAT. If the Host computer is directly connected to the Internet, it may not be possible to give the guest computers their own external IP addresses. In this case, VMware can perform as a NAT device, complete with a virtualized DHCP server to issue IP addresses to the guest operating systems? virtual NICs.
The physical NIC is connected to the outside world and then acting as a virtual NAT service. The virtual NAT service is connected to the virtual switch, where the virtual machines' NICs are connected, enabling them to connect to the outside world. Port forwarding can be set up on the virtual NAT device, enabling external devices to talk directly to virtual machines behind the NAT, exactly as with a typical physical gateway router.
In Host-Only network configuration mode, the virtual machines connect to a virtual network, only accessible by the host machine. Routing can be enabled between the host machine and the virtual machine. This is an interesting option if the design calls for running virtual machines on a different subnet than the host machine.
Another networking option is to run the virtual machine entirely within VMware, with no network access at all. This option may be useful in lab environments or for security purposes.