"Whoops!" knocks out .es for 2 hours

Written by Carel Solomon

As a "whoops!" echos through the corridors at Esnic, 400 000 .es domains are knocked out for two hours on Tuesday. And you thought the bigest threat to your business was your own servers failing?

Few people are actually aware how a company you have never dealt with before, or even heard of can knock your whole company out. The problem happened at Esnic - the top level registry for Spain, when "an error" during a software update meant that 400 000 thousand .es domains were unavailable for two hours.

This is because of the way dns works. Lets take genzee.co.uk. When you type in: www.genzee.co.uk in your browser, your pc tries to find the IP address associated to that name. It would start at the root (.) domain, and then make its way down to the host (www). Here it is step by step:

Firstly, the full name that is being looked up is: "www.genzee.co.uk." (not the . at the end). So your name server will first connect to the root servers and ask who manages the .uk domain, then, it will ask the .uk domain who manages co.uk. From there it will find the nameserver which manages genzee.co.uk. and finally ask the nameservers of genzee.co.uk to provide the IP for the host called "www". Now, if any of the nameservers serving root (.), .uk, .co.uk, or genzee.co.uk comes back with an error, either a "I'm broken" or "don't know the answer" the whole lookup will fail and no one can access your website, send you email and various services may fail.

It is a bit of a scary thought. Your domain availability is dependent on the top level registry running smoothly. Normally these registries have loads of redundancy to make sure they can carry on when disaster strikes, but all this is worthless if the software is configured wrongly. Sometimes it can be the silliest thing, a typo in a configuration file and the whole thing shuts down.

So, all the redunancy, checks, processes and policies cannot save you as long as human are involved, cause we all make mistakes sometime and sometimes a small "whoops!" hundreds and thousands of miles away can cause lots of pain on the other side of the world.

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