For a good part of yesterday Germany was unreachable on the Internet. 13.6 million sites with domains ending in .de, the top level domain used by the country, wouldn’t load. And email being sent to addresses at these domains was returned as undeliverable.

The problem happened when DENIC, the German Internet authority, uploaded new zone files that contained only partial data. But my goal is not to call attention to the cause, rather a potential solution.

Last year we introduced SmartCache, an OpenDNS invention and one of the most significant innovations the DNS has seen in its 25+ years. SmartCache works by automatically locating the last-known good IP address for websites that aren’t loading and can help in many cases where sites are unreachable, however temporarily.

While the nature of this particular issue would not have been entirely resolved by SmartCache, there are many others – that have taken millions of sites offline – that could be completely fixed for our users by our technology. SmartCache is available to all users free, but you have to enable it for your network. It’s a simple checkbox in Advanced Settings in your account. We purposely didn’t enable it across the board, because like everything we do, we wanted it to be your choice. After yesterday’s issue and a handful of others, however, we think maybe it should be on by default. We’re curious to hear your thoughts: does SmartCache provide enough value to warrant enabling it automatically for all of our users and making it a core OpenDNS feature?

I’ve been a bit quiet lately (look for that to change effective immediately), but I can assure you that our engineering team is working hard building new features that will make your Internet even safer, faster, smarter and more reliable than it is today. Stay tuned for more details, and in the meantime, let us know what you want us to build.

Today we announced one of the most significant DNS innovations of the last 25 years. SmartCache, our new DNS record-handling technology, renders frustrating authoritative DNS outages irrelevant for OpenDNS users. It’s both incredibly simple and invaluable to Internet users.

Here’s how it works: When an authoritative DNS provider suffers an outage, all of the Web sites it provides service to are taken offline. They’re inaccessible for everyone on the Internet. But no longer for OpenDNS users. Our servers will now immediately look for the last known good address for the site in our caches, and use that to load the site. So effectively OpenDNS users will be able to access Web sites that appear down for everyone else. For our millions of users at businesses, schools and libraries around the world, saving them Internet access interruptions and the time they waste is invaluable.

Authoritative DNS outages happen frequently and can be a big problem. Just a few weeks ago, it’s reported that major authoritative DNS provider UltraDNS suffered an outage that took Salesforce.com, Amazon.com and Petco.com offline for several hours. In such a case, SmartCache would fix the inaccessibility problem and allow people to visit the sites through the outage.

This is just the latest in a long series of DNS innovations we’ve developed and passed on to you. Most recently it was blocking the Conficker worm from phoning home. By blocking the domain names the worm used, we were and continue to be able to protect people around the globe. Trust that we’re committed to continue to innovate and give you easy-to-use services that make your Internet experience better.

SmartCache is available immediately as an opt-in feature. Just log in to your dashboard and look for the check box in your Advanced Settings. For those tech geeks, this only applies to queries where the authoritative server hands back a SERVFAIL response code in addition to any query that simply goes unanswered.

Let us know what you think of the new feature in the comments here.