Windows Firewall

Making Your PC Work Seamlessly with Windows Firewall

When you're using Duet Display to enhance your computer setup, it's essential to understand how it interacts with your Windows Firewall. In this article, we'll break down how it interacts with the Windows Firewall, and what you can do to ensure a seamless experience.

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What is Windows Firewall?

First things first, Windows Firewall is like a digital security guard for your computer. It helps protect your PC from harmful stuff on the internet. But sometimes, it can get in the way of certain apps like Duet Display if they're not properly introduced.

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How It Works

When you install the Duet PC Application, it's designed to add an exception for itself in the Windows Firewall. This is done using the configuration wizard within Advanced Installer.

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Without this exception, you may encounter some limitations:

No Wireless Air Connections: Duet won't be able to discover devices on your network, preventing you from making wireless air connections.

No Direct Incoming RDP Connections: While you can still make connections, they will go through a proxy, leading to higher latency.

However, this exception is added only if you're using the built-in Windows Firewall. If you have a third-party firewall, you might need to make the exception manually.

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Duet PC App

When you launch the PC Application, it checks whether an exception has been added for the current instance. This instance is specified by the LastDuetExeAddedToFirewall value in the duet.ini file. If not, and if it detects that you're not using a third-party firewall, it kindly reminds you to add one. You have the option to say "Yes" to this reminder, and Duet Display will add the exception for you. Saying "No" will dismiss the reminder.

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In case you're using a third-party firewall that's not the default Windows Defender, Duet Display recognizes this and provides you with an information message. It detects them by checking for names that don't contain "Windows Defender" or "Microsoft.". No further actions are taken regarding the Windows Firewall; it's just a heads-up.

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Taking Control with Command Line Options

There are some command line options available. These options let you manually add or remove the Duet Display exception from the Windows Firewall. However, keep in mind that these commands require elevated permissions (running the Command Prompt as administrator) to make changes to the Windows Firewall. Here are the options:

/ADD_TO_FIREWALL - This command adds the current instance of Duet Display to the Windows Firewall exception list.

/REMOVE_FROM_FIREWALL - Use this command to remove the current instance of Duet Display from the Windows Firewall exception list.

/REMOVAL_ALL_FROM_FIREWALL - If you've run Duet Display from a location other than the installation directory and want to clean things up, this command removes all instances of Duet Display from the Windows Firewall exception list.