Installation guide

CHAPTER 1 Introduction to VMware ESX Server
25
Private Virtual Ethernet Networks (VMnets)
VMnet connections may be used for high-speed networking between virtual
machines, allowing private, cost-effective connections between virtual machines. The
isolation inherent in their design makes them especially useful for supporting network
topologies that normally depend on the use of additional hardware to provide
security and isolation.
For example, an effective firewall can be constructed by configuring one virtual
machine on an ESX Server system with two virtual Ethernet adapters, one bound to a
VMnic (giving it a connection to a physical network) and the other bound to a VMnet.
Other virtual machines would be connected only to the VMnet. By running filtering
software in the dual-homed virtual machine, a user can construct an effective firewall
without the need for additional hardware and with high-performance virtual
networking between the virtual machines.
A similar approach can be used with multitier applications — with the Web or
application servers reachable from other systems but with the database server
connected only to the other tiers.
Internal
Network
Virtual
Machine
Internal
Network
Virtual
Machine
vmnic0
NIC
Physical NIC
vmnet_1
vmnet_0
Virtual
machine 1
Firewall
Virtual
machine 2
External
Web server
Virtual
machine 3
Firewall
Virtual
machine 4
On internal
network