I encountered a strange problem today. Someone could access their website from their cell phone but not their laptop and said a friend a few states away also couldn’t reach it. But I could reach it just fine.

When we started digging into what was going on, I found that he was using Google’s public DNS. When I switched to Google’s DNS, I couldn’t reach the site either.

So what is going on here? Apparently Google checks DNSSEC and a lot of other DNS resolvers do not. If it is misconfigured the site won’t resolve.

Here is where you can check your domain’s DNSSEC.

Need a fast and easy way to enable DNSSEC if your registrar doesn’t provide it? Check out Cloudflare.