How to Create an FQDN to 3CX Phone System that resolves locally

3CX Phone System requires that you have an FQDN that resolves locally. When a host is added to your DNS, a mapping is created between the domain and the IP Address of the Host. This guide will explain how to configure Microsoft DNS on Windows Server 2012 R2 to do this.

Prerequisites

  • A DNS Server in your local lan (Windows Server or any other configurable DNS Server)

Step 1: Enable the DNS Role

  1. Start “Server Manager”.add roles
  2. Click “Manage” on the top right of the Server Manager window and from the drop-down menu select “Add Roles and Features”.
  3. The Add Roles and Features Wizard will open. Click “Next”.
  4. Leave the default “Role-based or feature-based installation”. Click “Next”.
  5. Select the server that you wish to install the new role on. Click “Next”.
  6. Check “DNS Server” from the list. In the dialog window that pops up, leave the default settings selected and click “Add Features”. Click “Next” to proceed.
  7. On the Features page, click “Next”.
  8. On the DNS Server page, click “Next”.
  9. Click “Install”.
  10. When the installation is completed click “Close” and proceed to the next step.

Step 2: Add a New Zone

From the Server Manager application:

  1. Click “Tools” on the top right on the Server Manager window and from the drop-down menu select “DNS”.new zone
  2. The DNS manager will open. Right click on your server’s name and select “New Zone…”.
  3. The New Zone Wizard will open. Click “Next”.
  4. Leave the default “Primary zone” selected and click “Next”.
  5. Select “Forward lookup zone” and click “Next”.new zone wizard
  6. Fill in your zone name. In our example we used “example.local”. Click “Next”.
  7. In the Zone File page leave the default options selected and click “Next”.
  8. In the Dynamic Update page leave the default options selected and click “Next”.
  9. Click “Finish”.

Step 3: Add a New Host

Your newly created zone will now appear under Forward Lookup Zones:new host

  1. Right click on the zone you have just created and select “New Host (A or AAAA)…”.new host dialog
  2. Fill in the name of the host. In our example we used “pbx”.
  3. Fill in the local IP of the 3CX Phone System machine.
  4. Click “Add Host”. A dialog will appear confirming the that the record for “pbx.example.local” was added. Click “OK” followed by “Done”.

This is the FQDN you should use in the 3CX Phone System Setup in the Internal FQDN Section.

Test your DNS Entry

To make sure that your DNS Server resolves your FQDN to the correct IP Address do the following:

  1. Open a command prompt window on a computer in your lan.
  2. Type in nslookup followed by your domain name – Example nslookup pbx.example.local
  3. You should get as a result the IP Address of the host – in this example: 192.168.9.79