Specifications

CHAPTER 7 Networking
269
Understanding NAT
Network address translation — or NAT — provides a simple way for virtual machines
to use most client applications over almost any type of network connection available
to the host. The only requirement for NAT is that the network connection must
support TCP/IP.
NAT is useful when you have a limited supply of IP addresses or are connected to the
network through a non-Ethernet network adapter. NAT works by translating addresses
of virtual machines in a private VMnet network to that of the host machine. When a
virtual machine sends a request to access a network resource, it appears to the
network resource as if the request came from the host machine.
NAT uses the host’s own network resources to connect to the external network. Thus,
any TCP/IP network resource to which the host has access should be available
through the NAT connection.
The chief advantage of NAT is that it provides a transparent, easy to configure way for
virtual machines to gain access to network resources.
The following sections provide more information about NAT:
• Using NAT on page 269
• The Host Computer and the NAT Network on page 270
• DHCP on the NAT Network on page 270
• DNS on the NAT Network on page 270
• External Access from the NAT Network on page 271
• Advanced NAT Configuration on page 272
• Custom NAT and DHCP Configuration on a Windows Host on page 275
• Considerations for Using NAT on page 276
• Using NAT with NetLogon on page 277
• Sample Linux vmnetnat.conf File on page 278
Using NAT
The NAT device is connected to the VMnet8 virtual switch. Virtual machines
connected to the NAT network also use the VMnet8 virtual switch.
The NAT device waits for packets coming from virtual machines on the VMnet8 virtual
network. When a packet arrives, the NAT device translates the address of the virtual
machine to that of the host before forwarding the packet to the external network.