[notice]The use of services such as Tunlr, that provide access to geographically-blocked websites and services you might not normally be able to access, may be illegal in some jurisdictions.  We are not lawyers, so cannot comment further on this.  You are responsible for knowing your local laws.[/notice]

Tunlr is a service that describes itself as follows:

Do you want to stream video or audio from U.S.-based on-demand Internet streaming media providers but can’t get in on the fun because you’re living outside the U.S.? Fear not, you have come to the right place. Tunlr lets you stream content from sites like Netflix, Hulu, MTV, CBS, ABC, Pandora and more to your Mac or PC. Want to watch Netflix or HuluPlus on your iPad, AppleTV or XBox 360 even though you’re not in the U.S.? Tunlr lets you do this.

If you are in the U.S., Tunlr may allow you to access certain sites in Great Britain and elsewhere in Europe.  It does not yet allow access to sites in Canada (pity).  Again, we are specifically not saying that it is legal to to this, since were are not lawyers and cannot give legal advice.

You utilize Tunlr by setting your computer’s or router’s DNS addresses to Tunlr, but Tunlr does not want you to do this except when you are actually accessing content.  As their FAQ explains:

Why you shouldn’t set your DNS permanently to Tunlr

For speed, stability, privacy and security reasons we do not recommend to permanently set your computer’s or router’s DNS addresses to Tunlr. Setting the DNS permanently to Tunlr also puts a heavy strain on Tunlr’s network infrastructure. In order to render the permanent use of our DNS resolvers less attractive, we’re artificially delaying responses to DNS queries. What this means is that your Internet surfing experience will be a lot slower than if you’d just use your Internet service provider’s DNS resolver. However, your ability to download/stream audio or video content is not affected by this delay. To sum it up: do not use our DNS resolver for day to day web surfing.

The FAQ shows “links for more ideas about how to temporarily use our DNS resolver” and they do show some suggestions for OS X, but at this writing none of those links show the easiest way.  When you use the method described below, you will be able to simply click on the Apple logo in the top menu bar and select Tunlr as your DNS, or switch from Tunlr back to your usual DNS, like this:

Note that when you switch DNS servers in OS X your network connection will be momentarily interrupted, so you probably don’t want to do this while you have downloads or uploads in progress.

So, how do you set this up?  It’s relatively simple.  Go To System Preferences (which is another selection in the Apple menu shown above), and when it comes up, in the Internet & Wireless section click on Network.  You should then see a screen similar to this:

This image is from a system with only a wired ethernet connection – you may see additional connections. But in the left-hand menu you want to select the connection you’ll be using while using Tunlr, which is probably your wired (en0) connection unless you use wireless exclusively.

Before you go any further, click the Advanced button in the lower right corner, then on the next screen click the Proxies tab at the top:

What you want to see is what’s currently in the “Bypass proxy settings for these Hosts & Domains” text box.  If there is anything in that box, copy it and save it somewhere – you can open a TextEdit window and paste it in there temporarily if necessary.  Next, at the top, click on the Location dropdown and it should give you the option to Edit Locations, so select that:

Next you should see a popup window showing your existing locations:

Click the + in the popup and it should let you enter a new location, so enter Tunlr:

Click Done and the new location will be added. At this point it is not configured so you will likely be thrown offline, and you’ll see something like this:

Next click the Advanced button and go to the DNS tab, then click on the + and add the two Tunlr DNS addresses (69.197.169.9 and 192.95.16.109) as shown here:

After adding the two Tunlr proxies, click OK and then click Advanced again and go to the Proxies tab. What you want to do here is paste in any proxy information you copied from your original network connection back into the “Bypass proxy settings for these Hosts & Domains” text box.  So, copy that from TextEdit or wherever you saved it and paste it in here — it should look exactly as it did for the original connection:

Click OK and you should be taken back to the main Network settings window. Now it should show the two Tunlr DNS addresses:

The last thing to do is click Apply, which should enable the Tunlr location and start using the Tunlr DNS:

Note that the dot next to your network connection should have changed from yellow to green. Now open your web browser and go to the Tunlr status page (you can just click on that link). You are looking for the section near the bottom of the page headed Tunlr activation check, which should tell you whether or not Tunlr is activated.

Note that even if it says that you need to restart your device or computer after you change the DNS address, that is NOT true when you use this method.  Instead, when you want to access geographically-locked content that Tunlr knows about, you simply go to the Apple menu and select the Tunlr location, and when you are done accessing that content you go back the the same menu and select the Automatic location (or whatever your default location is called). Just keep in mind that any time you change locations, any in-progress communications (downloads or uploads) will be interrupted, and depending on the software and/or protocols used, you may need to restart those connections.