The outage affected about 900,000 sites. Although the mistake was corrected within an hour, other factors kept many .se sites and E-mail addresses offline for almost a full day. "Imagine the same thing happening to the .com domain, which has over 80 million domain names," Pingdom suggested. "Although not all of these are actually in use by Web sites or for E-Mail, the effects would still be huge and cause an unprecedented amount of downtime across the entire Internet."
E-Commerce site operators have enough to worry about without fearing the sudden disappearance of the Internet. But that's what confronted site operators in Sweden on Monday (Oct. 12). During routine maintenance of that nation's top-level domain, ".se," a tiny mistake caused the whole Swedish Internet to go dark. As documented by Sweden-based Web site monitoring service Pingdom, a script failed to include at its end a "trailing dot," essentially a period. "That trailing dot is necessary in the settings for DNS to understand that “.se” is the top-level domain," Pingdom noted. "It is a seemingly small detail, but without it, the whole DNS lookup chain broke down."