Tuesday, January 27, 2009

Remote Backups to Network Attached Storage

The Idea

The idea here is that you have a NAS (Network Attached Storage) drive that you’re using for Time Machine backups, like the setup I outlined in my “Using an AirPort Extreme and External Hard Drive as a Time Capsule” tutorial. Maybe you have a desktop at home, and a notebook that you travel with, and you’d like to continuously back them up to the same drive using Time Machine. I’ve seen other tutorials using Mobile Me / Back To My Mac to set this up, but I had no success with that approach. This is a pretty simple (not to mention FREE) way to achieve remote backups.


Any Mac running OS X 10.5.x, an AirPort Extreme and your favorite USB external hard drive. For my setup, I’m using an Intel iMac and pre-unibody MacBook, an 802.11n AirPort Extreme w/ Gigabit Ethernet and a Western Digital 500GB My Book Studio Edition.


1) The first thing I recommend is setting yourself up with a free OpenDNS account. See www.opendns.com for info. I also recommend downloading the OpenDNS Updater and putting it in your Login Items.

2) Next, set up a free Dynamic DNS account. This will give you a memorable URL to access your home network, rather than keeping up with an ever-changing IP address. www.dyndns.com

3) If you have a dynamic IP address, you will also want to install the DynDNS widget on a machine that doesn’t leave your local network. This will ensure that your DynDNS account always has the correct IP address. If you have a static IP address, you can skip this step. If you don’t know if your IP address is static or dynamic, it is most likely dynamic.

4) Launch AirPort Utility. Choose your AirPort Extreme and click “Manual Setup.” Under the AirPort pane, click the “Base Station” tab.

5) Click on the “Edit” button under the “AirPort Extreme Name” field. In the resulting window, check the “Use dynamic global hostname” box. In the “Hostname” field, enter the URL (with no http:// or www) that you just created. In the user and password fields, enter your DynDNS account name and password. It should look like the following example, only with your info in the fields instead of “example.”

From here on, you will need to perform these steps on whatever machine you plan on backing up remotely. In most cases this will be your notebook. If you haven’t done so already, I recommend doing your first backup of this computer locally as it will take quite some time. It is recommended that you quit all open applications before performing the following steps.

6) In Finder, under the Go menu, click on “Connect to Server.” Type in afp://example.dyndns.org, using your own URL. If you are prompted for a user name and password, use the same credentials that you used to set up your hard drive access in AirPort Utility.

7) Once the server has mounted, you can go into the Time Machine pane in System Preferences and select the drive. It will show up in the dialog box as “Hard Drive Name (example.dyndns.org).”

8) You’re going to want the computer to mount the server automatically on startup, that way Time Machine is still “set it and forget it.” In System Preferences, go into the Accounts pane. Click on the Login Items tab, then drag and drop the hard drive’s icon into the list. I prefer to have the “Hide” box checked to make this whole process run in the background.

9) Your final step is to connect to a different network and test your new backup configuration!

Bonus Features

When your hard drive is mounted, you have read/write access to everything on the drive, so in addition to backups, you also have a large file server at your disposal.

You can forward port 5900 to a machine on your local network, and then use a VNC client (such as Chicken of the VNC) to remotely access your home machine. For example, I can access my iMac at home using my MacBook any time I’m connected to the internet.


Keep in mind, you are limited by the download speed of your home internet connection, and (more importantly) the upload speed of your remote connection. This means that your backup speed will be significantly slower than when on your local network. For this reason, I do not recommend using this method for your first backup.

Remember that you are submitting non-encrypted data through the internet, and there is the chance it could be intercepted by a 3rd party. I would not recommend backing up sensitive data through this method.

It is very important that you have password protection not only on your hard drive, but also any machine attached to your network. Also, this should go without saying, but don’t go giving out your URL.

Other Notes

It does not appear to be necessary to change your backup disk to the local volume when connected to your local network. I have had no trouble backing up through this method while on my home network, and it appears to be taking advantage of local network speeds when doing so.

The backup process spends more time on preparing than usual. This appears to be normal for this situation.

I have not tested this functionality with a Time Capsule, but I don’t believe it will work. If anyone would like to try and report their results, I would love to add them to this tutorial.

Using an AirPort Extreme with a USB External Hard Drive as a Time Capsule

The Idea

This is a fairly simple setup, but requires a few little tricks to get everything running smoothly. I would argue that this setup is better than using a Time Capsule, as it offers a bit more flexibility.


Any Mac running OS X 10.5.x, an AirPort Extreme and your favorite USB external hard drive. For my setup, I’m using an Intel iMac and pre-unibody MacBook, an 802.11n AirPort Extreme w/ Gigabit Ethernet and a Western Digital 500GB My Book Studio Edition.


1) Plug the external hard drive directly into a Mac and fire up Disk Utility. Re-format the drive as Mac OS Extended (Journaled). Even if your drive is formatted this way out of the box (as mine was) it may be necessary to perform this step anyway.

2) Hook the drive up to the AirPort Extreme.

3) Launch AirPort Utility and click on “Disks” at the top of the window. Click on the “File Sharing” tab.

4) Make sure “Enable file sharing” is checked. The “Secure Shared Disks” option should be set to either “With a disk password” or “With AirPort Extreme Password.” Whichever you prefer will work. I did not have good results using accounts.

5) “AirPort Disks Guest Access” should be set to Not Allowed, keeping in mind that setting to Read Only will enable anyone who connects to your Extreme to mount the sparse-bundle and retrieve files from your backup, and setting it to Read and Write will give them the ability to delete files, or worse, your entire backup. Any of these options will allow you to perform a Time Machine backup, so you can allow guest access if you want, just be aware of the risks.

Make sure “Share disks over Ethernet WAN port” is checked.

6) I recommend NOT checking “Advertise disks globally using Bonjour” but this will not affect this setup.

7) Click on Update and wait for the Extreme to restart. Close AirPort Utility.

8) Open System Preferences and go to Time Machine.

9) You should now be able to select your hard drive for Time Machine. It will show up as the name of your AirPort Extreme, NOT the name of the hard drive.

If you are able to select your drive, you’re done! If not, follow these steps:

10) Open a Finder window. You should see your AirPort Extreme in the sidebar under “Shared.” Mount the server by clicking on it. If it prompts you for a user name and password, use the user name of your current OS X account, and the password you set up in AirPort Utility.

11) Your hard drive will show up as a folder. Double click to make sure you can open the folder.

Head back to System Preferences, where you should now be able to chose your AirPort Extreme connected hard drive for Time Machine Backups.

Bonus Features

You now have a Hard Drive connected to your network. This can be used to move files between machines, or even act as a server to store files you want easily accessible by multiple machines, such as your iTunes library. You can also connect the hard drive directly to a Mac for faster data transfer when doing major backups, or a full system restore.


This setup is NOT supported by Apple, and future software and/or firmware updates may break this functionality. As of OS X 10.5.6 and AirPort Extreme firmware v. 7.3.2, it works beautifully.

Using this networked hard drive as a file server for things such as an iTunes library is not recommended, because this leaves your iTunes library on only one hard drive, and will not be backed up in the event of a drive failure of your external hard drive.

Other Notes

I have been using this successfully since October 2008 and have yet to encounter an issue.