How to Keep a Folder in Sync on Two Devices with Resilio Sync (BitTorrent Sync)

Resilio Sync (formerly known as BitTorrent Sync) is a great way to keep files synchronized across multiple computers and/or other devices while avoiding the cloud and forking over money.

It works on just about any device you could possibly have, with apps available for Windows, Mac, Linux, iOS, Android, BSD, Amazon Kindle Fire, and lots of NAS manufacturers. Best of all: it’s free. There are some premium versions available that have access to a few more features you probably won’t need, and there’s a business subscription if you plan to use it at work, but we’ll be looking at the free model which is plenty sufficient for basic file sharing.

How does Resilio Sync differ from cloud services?

Resilio won’t store your data in the cloud. It’s peer-to-peer, so all of your data remains on your devices (and the devices of those with access to the folder you’re sharing). Resilio Sync uses the BitTorrent protocol to transfer file changes across the devices connected to the shared folder.

Resilio Sync features

We’ll do a quick run-through of what we like most about Resilio Sync, in case you’re contemplating whether or not this is the correct solution for your needs.

  • It’s free! It also won’t push upgrades on you or be annoying.
  • Compatibility with every major computer and mobile OS.
  • No limit of how much data can be stored or transferred.
  • Share and sync your folder with as many users and devices as you want.
  • Protection against accidental/regretful file deletions.
  • Grant either read access or read & write access to users.
  • No speed cap (many cloud providers will sync your data slowly at times).
  • Encrypted folder option is available.

Those features are what drew me to Resilio Sync. I’ve been using it for a long time in order to keep a folder on my PC shared and synced with a few family members, and it’s really worked well for this purpose.

How to setup a shared folder (on Windows 10)

If you’re ready to give it a try, head over to Resilio Sync’s site and download the installer. You can install with the default settings and complete the installation by choosing a name.

To create a folder that you can share out with other people (or connect to other devices of yours), click the plus sign and standard folder.

Now you’ll need to select where the folder is located. If you haven’t already made one, now would be a good time. Keep in mind that if you pick a folder with a lot of files already in it, those files will begin transferring to any device that you connect to this folder.

You’ll allow other users/devices to access this folder by either giving them a link, key, or QR code that Resilio Sync generates for you.

Before generating the link through the Email or Copy button, be sure to configure the permission and security settings you’d like. “Read Only” means that the user/device can access the files but not edit them or add their own. “Read & Write” grants that user/device full access to add, edit, or delete files.

Now that your folder is setup, other devices can access it with the link (or key or code) you generated.

They can just click the link or scan the QR code, or enter it manually under ‘Enter a key or link.’

You’ll be asked to select a sync folder on the new device as well. Resilio Sync will then make sure that those two folders are kept in sync.

You can now begin to share or collaborate in the synchronized folder. You’ll know that Resilio Sync is busying syncing changes if you see it animating in the taskbar.

Detailed stats are displayed at the bottom of Resilio Sync’s main screen:

Recovering deleted files

Another feature we’ve found useful is that if someone in your group deletes a file, you can still access it on your device in the hidden ‘.sync’ folder. The deleted files are kept in .sync\Archive in case you still need them or wish to restore them.

What is UPnP and How Do I Enable/Disable It?

Universal Plug and Play (UPnP) is a setting available in most routers that allows you to skip the manual configuration of port forwarding (hence the name plug and play).

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UPnP can detect services running on your PC and instruct your router to accept incoming connections on the appropriate port. This means that if you are hosting a service which you’d like to make accessible over the internet (such as a gaming server), you don’t need to do any extra configuration in your router to accept the incoming connections.

Keep in mind that sometimes UPnP is enabled by default, so you may not even need to do anything to start accepting incoming connections over the internet.

Is UPnP a security concern?

The short answer is: yes, it can be. There’s a reason that routers used to drop all incoming connections by default before UPnP become standard and ubiquitous across all brands of routers. Securing your PC from malicious attacks is the job of your firewall (Windows Defender in most cases), but it’s also the job of your router. Routers without UPnP enabled will drop incoming connections, and that’s good.

At the same time, it also means that hosting a gaming server or other service that needs to be accessible from the internet is a little more challenging without UPnP. UPnP is just for convenience and makes it so a user can host a service without having to worry about figuring out how to set a static IP address and configure port forwarding.

There have been a lot of reports of hackers exploiting UPnP to launch malicious attacks. But don’t hit the panic button: as long as you have your firewall enabled and you keep your software up to date, it’s very unlikely that you’ll be affected by this kind of exploit.

In conclusion, it’s a good idea to keep UPnP disabled and just manually configure port forwarding when needed. If you find that UPnP has really made things more convenient for you, then enable it but be cognizant that there is a small risk associated with doing so.

How to enable or disable UPnP

There are a lot of router makes and models out there, so the instructions for enabling or disabling UPnP is going to vary widely. We’ll show you the step-by-step using a Linksys router. If you have a different brand, you’ll have to improvise on some steps but you should find that the process is very similar.

Start by getting the IP address of your router. Open a command prompt by going to Start and typing ‘cmd.’

In the command prompt, type ‘ipconfig’ and press enter. Your router’s IP address will be listed under ‘Default gateway.’

You can see in this example that our router’s IP address is 192.168.1.1. Type that into the address bar of your web browser to bring up your router’s configuration page.

The default password for a Linksys router is ‘admin.’ That may be true for your router as well, or you may need to look for a label on your router to find the correct password.

Once you’re logged in, click on Connectivity (if your settings look different, you’ll have to poke around in the settings to find UPnP, or consult the manual/Google for where to find it), and then Administration.

Here you’ll find the setting to enable or disable UPnP. After making your changes, click OK to save them.

How to Forward Ports on Your Router

When you’re hosting a service from your PC and you need to accept incoming connections, you’ll need to configure your router to allow those connections by forwarding a port or enabling UPnP.

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If you are hosting a service from your PC, such a gaming server, you can allow others to connect to your server by giving them your IP address. Unless your router has been properly configured, it will either block their incoming connection automatically because of security settings, or it will not know which device on your network to send the request to and resort to refusing the connection.

You basically have two options, then. You can manually forward the appropriate port(s) and allocate a static IP address for your PC, or you can enable UPnP on your router. See our guide on enabling UPnP if you’d like to try that route, or continue reading to learn how to forward ports on your router.

What is port forwarding?

By configuring your router to forward a port to your PC, you are telling it to accept that incoming connection and also giving it information about where to send it. Port forwarding is a manual process that must be done in the router’s settings.

Keep in mind that in order for your forwarding settings to remain in place between reboots (of either the PC or the router), you should configure a static IP address for your PC in the router’s settings because the local IP address of your PC (the one that the router uses to communicate with it), likely changes every once in a while, which means your forwarding settings would need changed too.

To prevent that, we can add a setting to your router that tells it to always hand out the same IP address to your PC. We’ll go over how to set that up while also making the necessary configurations for port forwarding.

How to forward a port on your router

Linksys is a popular consumer brand of routers, and we’ll be using one in this guide to show the steps to forward a port and allocate a static IP. If you have a different brand of router, the instructions should be pretty similar, you’ll just have to improvise where applicable.

Accessing your router’s settings page can be done from your PC (or phone, or any device that has a browser and is connected to your network). The first thing we need to do is figure out the local IP address of the router. It’s normally in the 192.168.x.x range, but it can vary by manufacturer.

Start by opening a command prompt by typing ‘cmd’ in the Start menu.

In the command prompt, type ‘ipconfig’ and press enter. What we’re looking for in this output is the IP address of the ‘default gateway’ (a fancy term for your router).

As you can see in the screenshot above, the IP address of my router is 192.168.1.1. Type that address into the URL bar of your browser in order to access your router’s configuration page.

You’ll be asked to enter a password on this page. For Linksys and a lot of other popular manufacturers, it’s ‘admin’ by default. Your password may be on a label on the router itself, so check there if you’re not sure.

We’ll start by configuring a static IP address for our PC. In the Linksys menu, those settings can be found under ‘Connectivity.’ You’ll have to poke around if you’re using a different brand. You’ll know you’re in the right menu when you see something called ‘DHCP reservations.’

On this router, the setting for DHCP reservations was under Connectivity > Local Network.

In the DHCP reservation menu, you can select your PC (the one running the service you’re hosting), click on ‘Add DHCP Reservation,’ and click OK to save the setting.

If your menu doesn’t have your devices listed, you may have to enter the IP address of your PC manually to create the reservation. Refer back to the command prompt to figure out what your PC’s IP address is.

Either way, take note of your IP address (either by seeing it in the DHCP list or the command prompt) because you may need it when filling out the port forwarding settings.

Port forwarding is found under Security > Apps and Gaming in our Linksys router. From here, we can choose to forward a single port or a range of ports. Select whichever is applicable for you, then fill out the ports and your IP address, and click OK.

Your service should now be accessible from the internet. You can use this port forwarding tester website to make sure that it’s working correctly.

Share your public IP address with whomever you’d like to give access to. Keep in mind that you may also have to configure your firewall settings and/or disable your anti-virus, since both of those are also known to block incoming connections.