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What Nobody Tells You About Using an Old Laptop as a Second Monitor

Discover the surprising truth about turning your old laptop into a **second monitor* - for Linux. It's easier than you think with this smart trick.

0 views·6 min read·Jun 19, 2026
Use a laptop as a 2nd display on Linux using FreeRDP

Do you ever feel like you just don't have enough screen space? You're trying to multitask, keep an eye on a chat, and work on a project all at once. Your main monitor feels cramped, and buying a brand new one can be expensive.

What if we told you there's a hidden way to expand your digital workspace, using something you might already own? Forget about spending hundreds of dollars. The answer could be sitting in your closet, gathering dust right now.

The

Dream of More Screen Space, Made Real

Imagine having a dedicated screen for your email, a video, or extra notes while your main monitor stays focused on your most important task. Multiple monitors make a huge difference for productivity. They let you spread out your work and see everything at a glance.

However, the idea of buying another monitor can be a turn-off. New screens cost money, take up desk space, and sometimes require special cables. Many people wish for more screen area but put off the expense or the hassle.

This is where a clever, often overlooked technique comes in. It lets you use an old laptop, or even a tablet, as a fully functional second display for your main Linux computer. It's a way to reuse old tech and gain a big boost in how you work.

Why Your Old

Laptop is Perfect for the Job

Most homes have an old laptop tucked away somewhere. Maybe it's too slow for modern games, or its battery doesn't last long. But it still has a perfectly good screen, a power supply, and a network connection.

Traditional ways of connecting a second screen usually involve an HDMI or DisplayPort cable. These cables typically send video *out

  • from a computer, not *into

  • a laptop screen. Laptops generally don't have video input ports for this reason.

So, how do you get around this limitation? The trick involves making your main computer *think

  • it has another monitor connected. Then, you use a special kind of remote connection to stream that virtual screen to your old laptop. It's a smart workaround that opens up new possibilities.

The Clever Trick: Dummy

Plugs and Remote Desktops

The core of this method relies on two key ideas. First, you need to trick your main Linux computer into believing a second monitor is physically attached. You do this with a *dummy HDMI plug

  • (sometimes called a headless ghost adapter). These small, inexpensive devices plug into your video output and make your computer detect a monitor, even though there isn't a real one.

Once your main computer thinks it has an extra screen, you need a way to see what's on that screen. This is where a remote desktop protocol (RDP) comes in. RDP is a system that lets you view and control a computer screen from another computer over a network. You'll set up your main Linux machine to *serve

  • this virtual screen, and your old laptop will *receive

  • it.

Setting Up Your Main Linux Machine

To make your main Linux computer ready, you'll need to install a program called Xrdp. This program acts as the RDP server. It takes the video signal from your main machine, including the signal from your dummy plug, and makes it available over your network.

You can usually install Xrdp with a simple command in your terminal. For example, on Ubuntu or Debian-based systems, you might type sudo apt install xrdp. After installing, you'll want to restart the Xrdp service.

Next, you'll configure your display settings. Your Linux system should now detect the dummy monitor. You can arrange it next to your main screen, just like a physical second monitor. Choose the resolution you want for your laptop screen, keeping in mind its native resolution for the best look.

Bringing Your Laptop Back to Life (as a Screen)

Now for your old laptop. It will act as the viewer for your new second screen. You'll need an RDP client program installed on it. A popular and effective client for Linux is FreeRDP, often used with the command xfreerdp.

First, make sure FreeRDP is installed on your old laptop. On many Linux systems, you can install it with sudo apt install freerdp2-x11 or similar commands. Once installed, you can connect to your main computer using a simple command that includes the IP address of your main machine and the desired resolution.

For example, a command might look like xfreerdp /v:192.168.1.100 /size:1920x1080. The /v part specifies the IP address of your main computer, and /size sets the resolution. This command will open a window on your old laptop showing your new second display, streamed live from your main machine.

Getting the Best Experience

To make sure your new second screen feels smooth, a few things can help. A *wired network connection

  • (Ethernet cable) between your laptop and your router, and your main computer, will always perform better than Wi-Fi. This reduces lag and makes the video stream more responsive.

Choosing a lower resolution for your dummy monitor can also improve performance. While your laptop might support a high resolution, streaming a slightly lower one, like 1920x1080, often results in a smoother experience. Experiment to find what works best for your setup.

Remember, this setup is primarily for displaying content. While you can technically interact with the laptop's keyboard and mouse, it's often more practical to use your main computer's input devices. The goal is to extend your visual workspace, not necessarily to create a fully independent second computer.

Common

Problems and Quick Fixes

Sometimes things don't work perfectly the first time. If you can't connect, double-check the IP address of your main computer. Make sure both machines are on the same local network. Firewall settings on your main Linux machine might also block RDP connections, so you may need to allow traffic on port 3389.

If the resolution looks wrong or blurry, ensure your dummy plug is detected correctly by your main computer. Also, verify that the /size parameter in your xfreerdp command matches a resolution supported by your laptop screen and configured on your main system. Sometimes restarting Xrdp or even your main computer can resolve display issues.

Performance problems, like slow updates or choppy video, are almost always related to your network. If a wired connection isn't possible, try to minimize other network activity. You can also try adjusting the xfreerdp command with options like /bpp:16 to reduce color depth, which uses less bandwidth.

This ingenious method offers a powerful, low-cost way to expand your screen real estate. It breathes new life into old hardware and shows how a little technical know-how can solve common problems. No need to buy new, just repurpose what you already have.

So, before you consider buying another monitor, take a look at that old laptop. With a small adapter and a few commands, you could have a whole new world of screen space at your fingertips. It's a smart, green, and budget-friendly upgrade that truly changes how you work.

How does this make you feel?

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