6.0.3

Table Of Contents
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Virtual Machine 2 runs a Web server, and Virtual Machine 3 runs as an application server. Both of these
virtual machines are connected to one virtual switch.
The Web server and application server occupy the DMZ between the two rewalls. The conduit between
these elements is Standard Switch 2, which connects the rewalls with the servers. This switch has no direct
connection with any elements outside the DMZ and is isolated from external trac by the two rewalls.
From an operational viewpoint, external trac from the Internet enters Virtual Machine 1 through
Hardware Network Adapter 1 (routed by Standard Switch 1) and is veried by the rewall installed on this
machine. If the rewall authorizes the trac, it is routed to the standard switch in the DMZ, Standard
Switch 2. Because the Web server and application server are also connected to this switch, they can serve
external requests.
Standard Switch 2 is also connected to Virtual Machine 4. This virtual machine provides a rewall between
the DMZ and the internal corporate network. This rewall lters packets from the Web server and
application server. If a packet is veried, it is routed to Hardware Network Adapter 2 through Standard
Switch 3. Hardware Network Adapter 2 is connected to the internal corporate network.
When creating a DMZ on a single host, you can use fairly lightweight rewalls. Although a virtual machine
in this conguration cannot exert direct control over another virtual machine or access its memory, all the
virtual machines are still connected through a virtual network. This network could be used for virus
propagation or targeted for other types of aacks. The security of the virtual machines in the DMZ is
equivalent to separate physical machines connected to the same network.
Creating Multiple Networks Within a Single ESXi Host
The ESXi system is designed so that you can connect some groups of virtual machines to the internal
network, others to the external network, and still others to both—all on the same host. This capability is an
outgrowth of basic virtual machine isolation coupled with a well-planned use of virtual networking
features.
Figure 83. External Networks, Internal Networks, and a DMZ Configured on a Single ESXi Host
physical network
adapters
External
Network 1
Internal
Network 2
External
Network 2
Internal
Network 1
ESXi
VM 2
internal
user
VM 3
internal
user
VM 4
internal
user
VM 5
internal
user
VM 6
firewall
server
VM 7
Web
server
VM 8
firewall
server
VM 1
FTP
server
Internal NetworkExternal Network DMZ
Chapter 8 Securing vSphere Networking
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