Remote control a PC with a smartphone

With this guide we'll show you how to control a computer with a smartphone. Not only another cool thing to show off the capabilities of a modern handset but also really useful for administrating your PC remotely, helping out friends with technical problems and setting downloads going so they're ready when you get home.

It's not too complex to setup, will work on most current smartphones and shouldn't cost a penny.

What you'll need

• Smartphone

I'm using an Android handset for this guide, but VNC software is available for iPhone, BlackBerry and Nokia phones.

• VNC server software

Server software is installed on your computer to enable clients to connect from a remote location. Though this guide is for Windows, VNC software is available for all platforms and the basic configuration options will be similar.

Windows: UltraVNC

Mac: Vine

Linux: TightVNC

They aren't the only options, there are lots of VNC tools for each platform so search around if these don't work for you. Also worth noting that Mac OS X users have the option of using the Apple Remote Desktop program.

• VNC client

Now you have a server you'll need a viewer for your phone. I'm using the free android-vnc-viewer, many others are available for Android some of which will cost you money. Use whichever you prefer - they should all connect to standard VNC tools like those listed above.

iPhone users should check out Mocha VNC. For other smartphone platforms check your respective app store or run a Google search.

Configuring the VNC server

After installation start the server-side application to change the settings.

The main options are...

• Port

By default VNC servers listen on port 5900, . There's also a HTTP port which makes a system accessible from a web browser (make sure the Java viewer option is enabled for HTTP access).

• Password

VNC servers are obviously a security risk since anybody could access the system so a strong password is essential. Use more than eight characters with a mix of numbers and letters. It's also possible to set a 'view only password' so your system can be viewed without allowing input control.

• Query

Query on connection will cause an alert to show asking if the user wants to allow remote access, and it can be set to refuse or allow after a set time. Obviously setting this to refuse when no one is home will prevent you from logging in, but it's useful if the owner would like to control when it's accessed rather than leaving the PC available all the time.

• Remove wallpaper

This stops the desktop wallpaper from showing on the viewer and makes screen updates much faster. Always leave it enabled. UltraVNC also has the ability to disable Windows Aero desktop effects for increased performance, similar functions may be available on other platforms.

Settings will differ depending on operating system and VNC app but these basic functions should remain much the same across all platforms.

Setting up the router

Once the VNC server is running it should be accessible immediately from within your own network, test it by connecting the smartphone to the Wi-Fi or using a viewer on another PC then accessing the VNC-enabled system with its internal IP (usually 192.168.1.64 or similar, Windows users can hold the mouse over the icon to display this or go to a command line prompt and type ipconfig).

However, try from an external connection and it's probably not going to work because the router will block it. So the final step required is to tell the router to allow the VNC viewer access.

This is done using port forwarding, which instructs it to let through traffic on the port at which the VNC server is listening (the same one you set during the server configuration).

Due to the huge variation in types of router it is impossible to give exact instructions on how to do this for every different model, but here's how it's done on an O2 broadband router:

1) Login to the router (if you're not sure how check the manual or read more in our router guide)

2) Click Toolbox > Game & Application Sharing > Assign a game or application

3) Click the Application drop-down box and scroll to the bottom to find 'VNC'.

4) Click the Device drop-down box and select the computer which has VNC installed. This may have a generic ID or a name you chose during installation of the operating system.

5) Click Add

That's it. The O2 router makes it very, very simple and it should be just as easy on other modern routers.

Sometimes you may need to manually configure the port forwarding. With O2's Thompson routers this is done by clicking 'Create a new game or application' instead of 'Assign'. Enter a name for your new setting, choose manual entry and click Next. Type the VNC listen port in both Port Range boxes, leave Protocol as Any then click Add. You can then assign this new setting by following the steps above.

This should not differ greatly no matter which router you use, but if you do get stuck head over to the extremely helpful PortForward.com, which has a huge database of router models with port forwarding guides to each. It even has step-by-step help for specific VNC server applications.

Note that if you changed the port settings from the default 5900 in the VNC server you'll almost certainly have to manually enable port forwarding.

Accessing the PC

Now that VNC is setup and the router is letting in visitors, you can login in with your smartphone.

Install your viewer app of choice and enter the configuration. It will ask for the IP address, password and port. It may also ask for a nickname, which isn't important.

To get your IP address just go to WhatIsMyIP.com and note down the number.

Password and port should be self explanatory...make sure they match the VNC server configuration.

When you click connect (or login, or whatever it may be called on your particular mix of phone and app) it'll take a few seconds to handshake with the server and load the desktop.

Be prepared for it to be sluggish, even on a 3G connection. The response will be slow and the screen takes time to refresh. It's not going to let you work on the computer as though you were sat in front of it, but loading applications and changing settings is all doable.