Missing dot drops Sweden off the Internet

15.10.2009
What was essentially a typo last week resulted in the temporary disappearance from the Internet of almost a million Web sites in Sweden -- every address with a .se top-level down name.

According to Web monitoring company Pingdom, which happens to be based in Sweden, the disablement of an entire top-level domain "is exceptionally rare. … Usually it's a single domain name that has been incorrectly configured or the DNS servers of a single Web host having problems. Problems that affect an entire top-level zone have very wide-ranging effects as can be seen by the .se incident. … Imagine the same thing happening to the .com domain, which has over 80 million domain names."

The total blackout of .se lasted for about an hour and a half, Pingdom says, although aftershocks continued for days.

"The .SE registry used an incorrectly configured script to update the .se zone, which introduced an error to every single .se domain name," Pingdom says. "We have spoken to a number of industry insiders and what happened is that when updating the data, the script did not add a terminating '.' to the DNS records in the .se zone. That trailing dot is necessary in the settings for DNS to understand that '.se” is the top-level domain."

Sweden's Internet Infrastructure Foundation, which administers .se, issued a statement saying essentially that things could have been a whole lot worse had it not been so much on the ball. … Good thing.