Companies can reduce the risk from the type of cyber attack that took out major websites on Friday by using multiple vendors for the critical internet service known as a domain name service, or DNS, companies and security experts said on Sunday.

"We have advocated for years for redundancy in your infrastructure," said Kyle York, chief strategy officer for Dyn, the New Hampshire DNS provider that was attacked on Friday. "I don't think you can ever be safe enough or redundant enough."

Hackers unleashed a complex attack on the internet through common devices like webcams and digital recorders and cut access to some of the world's best known websites on Friday, a stunning breach of global internet stability. York said clients who used multiple servers "saw less of an impact."

Using multiple DNS providers can, however, make managing traffic more complicated and costly, experts said. Friday's cyber attack alarmed security experts because it represented a new type of threat rooted in the proliferation of simple digital devices such as webcams. Such devices often lack proper security, and hackers found a way to harness millions of them to flood a target with so much traffic that it can't cope. The attack on Dyn and the resulting outage started in the Eastern United States on Friday and then spread to other parts of the country and Europe, affecting companies including Twitter and Paypal. DNS providers such as Dyn act as a switchboard for internet traffic.

"It's important to implement diversity geographically, as well as architecturally," for a defense against domain name service attacks, said Andy Ellis, chief security officer at Akamai Technologies, which helped Dyn recover on Friday. Businesses can choose up to eight authoritative domain service providers, and some of the hardest-hit sites were customers who only picked Dyn.