Working with NLB - RDP Not Working with Black Screen. Some Considerations

Windows Network Load Balancing (NLB) is a feature that distributes network traffic among multiple servers or virtual machines within a cluster to avoid overloading any hosts and improve performance. The Network Load Balancing feature uses the TCP/IP networking protocol to route traffic to different hosts based on a user's settings and a proprietary Microsoft distribution algorithm. The feature is available in Microsoft Windows Server 2008, 2008 R2, 2012 and 2012 R2 operating systems.

Network Load Balancing can also ensure network traffic is re-routed to remaining hosts if one or more hosts within the cluster fail unexpectedly. A Network Load Balancing cluster can scale up to 32 servers/nodes.

We can use NLB when configuring Terminal Servers High Availability. Let's take for instance the picture below:

All the Internal Users and possible External Users can use the VIP Address of the NLB to reach one of the Terminal Servers. If one Server is Down, the NLB automatically redirects all the requests to the remaining one. The same happens with WebServers.
 

Let's see some of the most common problems and considerations:

 

Root Access Technicolor Router

I noticed that my public IP was pingable from the outside, but I never had the chance to disable this option. Yesterday, I spent some time and I found that this option is only visible by command line and we need to have ROOT on the device (WTH). By default, the ISP only provides us the Administrator user to do some "basic" tasks. So, I had to have root access :)

The router in question is a Technicolor TG784n.v3 but it might work with other versions.

Let's see how to do it!

Windows Time Server Configuration

Usually when I install a new Windows domain or want to change the time server, I have to perform some steps. The settings are as follows: