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Now that we have our additional VPN server configured and deployed,

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we can move on to the task of enabling load balancing.

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Now, as I stated previously,

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I recommend using an external load balancer for best performance,

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but unfortunately,

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covering all the configuration options for third‑party load

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balancers out there is out of scope for this course.

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However,

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Windows Network Load Balancing is a viable

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alternative to an external load balancer,

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and it is easy to configure and costs nothing,

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so we'll take a look at that now.

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Before we get started, I want to talk about some of the requirements for NLB.

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The first thing we need to do is install the NLB role,

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and we need to do that on all of the servers in the

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cluster prior to configuration.

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Next,

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we need to set aside an IP address for the virtual IP address. This is

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going to be the IP address that we address the cluster as,

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and this needs to be an IP address from the same subnet as

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the dedicated IP address or the IP address that the VPN

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servers are physically numbered into.

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And then finally,

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just a quick word about operating mode. Network Load Balancing

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has a couple of different operating modes,

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the most common are unicast and multicast.

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And we recommend using a unicast wherever possible,

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but sometimes we have to use multicast.

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So,

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unicast works well in physical environments. Oftentimes, when we work

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in virtual environments, you'll have to switch to multicast mode just

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because of the subtleties and nuances of virtual networking, and there

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may be some additional configuration required to support multicast

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mode. Specifically,

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you may need to create static ARP entries on border routers or

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firewalls to support that, so that's in a bit of an advanced

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configuration. We're going to use unicast mode,

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and when that works, it works well,

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but you may have to use multicast mode in your environment depending on your particular hypervisor.