According to Royal Pingdom, who is based in Sweden, routine maintenance to the top-level domain — .se — turned into anything but a routine update. An error was introduced that effectively brought down Sweden's internet as a whole for about an hour, starting at 21:45 local time.
Essentially anyone trying to access a .se domain between 21:45 and 22:43, and thereafter due to complications restoring access, would have received a DNS error. That's a pretty astounding fact, and quite a lengthy period of time for an entire country's internet to be inaccessible due to an error in an otherwise routine procedure.
Royal Pingdom writes of the error:
"The problem happened during planned maintenance of the .se domain. The .SE registry used an incorrectly configured script to update the .se zone, which introduced an error to every single .se domain name.
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. It is a seemingly small detail, but without it, the whole DNS lookup chain broke down."
We can only imagine the disastrous side effects of such an all-encompassing internet outage; countless complaints, online retailer woes, and a plethora of businesses had to be negatively affected by the down time.