A software configuration update triggered a bug in the DNS (domain name system) system.

SAN FRANCISCO (AFP) - Websites were briefly knocked offline Thursday after a software update triggered a glitch at network specialty firm Akamai.

Reports of internet outages from locations around the world spiked at website Downdetector, with US-based Akamai saying some websites were offline for as long as an hour.

"A software configuration update triggered a bug in the DNS (domain name system) system, the system that directs browsers to websites," Akamai said in a post.

"This caused a disruption impacting availability of some customer websites."

Rolling back the software update fixed the problem, according to Akamai, which apologized for the trouble.

The disruption affecting banks, airlines and other online services came just weeks after Akamai was at the heart of a major online outage that hit bank and airline websites on both sides of the Pacific.

Akamai at that time said around 500 of its customers were briefly knocked offline on because of a problem with one of its online security products.

The incidents draw attention to the stability of economically vital online platforms and the key role that a handful of little-known "CDN" -- content delivery network -- companies play in keeping the web running.

In June, US media and government websites, including the White House, New York Times, Reddit and Amazon were temporarily hit after a glitch with cloud computing services provider Fastly.

Fastly offers a service to speed up loading times for websites.