How to setup a Dynamics NAV Cluster

How to setup a Dynamics NAV Cluster

Windows Server 2012 R2 includes a builtin Network Load Balancer feature. The load balancer inspects the destination address of an incoming packet and forward its to a clusternode.



Multihomed Network Routing

Open cmd

Get int index Route print

Route-p add ip mask 255. Metric 1 if 12

Install NLB


Create an NLB Cluster

Add second node


Netstat Filtering

When you perform a netstat -noa you could encounter a huge list with information. To filter through this list use piping. Like this:

netstat -noa | find “13000”

You now only see processes which listens to port 13000.

How to use telnet to check for open ports

Sometimes when installing a new NAV version for a customer I experience problems like a service tier which won’t start. Based on examination of the error in the Application Error log I will then use Telnet to check whether a port is opened or not.


  1. First install Telnet. By default this feature isn’t installed. You can accomplish this quick with Powershell:
    Install-WindowsFeature -Name Telnet-Client -Verbose
  2. Now you can open a telnet session. First start a Command Prompt. Now type:
     telnet ipadress port
  3. If you see this then the port is open from the current machine to the IP and port you specified:
    Telnet Port Opened
    If you see this then the port is closed:
    Telnet Port Closed
    In the example above I checked if port 1433 is open on the SQL Server. This way I can verify it isn’t a firewall issue.