In this article, we will be reviewing the configuration of headless clients with your Host Havoc hosted Arma 3 server.

To start, there are two methods of using Arma 3’s headless client feature:
1. To use your Host Havoc Arma 3 server as the headless client and have it connected either to an outside server, or another Host Havoc hosted Arma 3 server.
2. To connect another instance to your Host Havoc hosted Arma 3 server.

The configuration of this feature is not all that difficult. However, certain barriers may exist, preventing connections from being either maintained or established altogether. Here is a short list to name a few:
- Firewall rules in place preventing connections
- Anti-virus running on the system disallowing the connection or blocking the program entirely
- Misconfigured config files
- Mission is not designed to integrate with a headless client connection

Next, here are some useful articles referencing various information on headless clients (when one should be used, issues encountered through their use, etc.). It is strongly advised that you review this information before setting anything up.
Official wiki article: https://community.bistudio.com/wiki/Arma_3_Headless_Client
Third-party guide by “Monsoon”: https://www.dropbox.com/s/1n5a8entg3hvj5z/A3_hc_tutorial.pdf?dl=0

Configuring your Host Havoc hosted server

Option 1: Using the Host Havoc Arma 3 server to be the headless client and connect to an external instance
Step 1: Log into your game control panel.

Step 2: Click on the 'More' icon located directly to the right of the Start/Restart buttons

Step 3: In the 'More' section, click on "Change to HC/Arma 3 server" and choose Headless Client and click on run.

Step 4: Navigate to the command line manager and create a custom command line if you have not already.

Step 5: Fill in the “Client Connect info” textbox with the IP, followed by your port. For instance, if your other server has an IP of 123.123.123.123 and a port of 2300, you’d set the textbox to: 123.123.123.123:2300
Step 6: Save the command line and click “Select” on the right-hand side of the command line manager.

Option 2: Using another instance as an HC to connect to your Host Havoc Arma 3 server
Step 1: Ensure you’ve reviewed the previously referenced resources. There is much information to be had.
Step 2: Log into your game control panel.
Step 3: Navigate to the “Configuration Files” menu.
Step 4: Open the “server.cfg” file in the text editor.
Step 5: Add the headlessClients[] array somewhere in the server.cfg on its own line, as referenced on the wiki page. Add the headless client’s IP accordingly.
Step 6: Ensure your mission is compatible with headless clients. This is all covered in the previously referenced resources.