Internet security experts say that misconfigured DSL and cable modems are worsening a well-known problem with the Internet's DNS (domain name system), making it easier for hackers to launch distributed denial-of-service (DDoS) attacks against their victims.
For National Veterinary Associates, the decision to block the Web was sealed with a virus.
Various challenges are making many operators hesitate to adopt DNSSEC (Domain Name System Security Extensions) to prevent hackers from tampering with DNS information and redirecting Web traffic, according to a study from European Union's cybersecurity agency.
An attack on the servers of a domain registrar in China caused an online video application to cripple Internet access in parts of the country late on Wednesday.