Chapter 7. Virtual Networking

More often than not, you want virtual machines to be able to reach the physical world, and the only way they can accomplish that is through virtual switches. Virtual switches are software-only devices and exist solely in the VMkernel on your ESX host. Think of them as the bridge that your virtual machines cross to get to your physical network.

In this chapter, we examine how to setup virtual switches, connect virtual machines to them, how to make virtual switches fault tolerant, and how to assign various policies to ports on a virtual switch.

Virtual Switch Options

Many configuration options exist for virtual switches. You can assign virtual local area networks (VLANs) and security as well as limit the amount of traffic that virtual machines can generate. Additionally, you can assign many NICs to a virtual switch for load balancing and fault tolerance. NICs are called uplink adapters. Multiple uplink adapters are a wise choice for production environments.


If you want an isolated virtual network — for testing or any other reason — you can set up a virtual switch without an uplink adapter. Any virtual machines plugged in to a disconnected switch can see only each other: They can never see the outside world or virtual machines connected to any other virtual switch. This lets you create a great isolated test environment.

However, if you want your test environment to access the outside world, you certainly can. Virtual machines can be set up with two network ...

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