On July 9, the FBI will close down a network of DNS servers that many people have been depending on for proper Internet access. These servers were originally a part of a scam where a crime ring of Estonian nationals developed and distributed a malware package called DNSChanger, but which the FBI seized and converted to a legitimate DNS service.

This malware scam has been widespread enough that even third-party companies like Google and Facebook and a number of ISPs like Comcast, COX, Verizon, and AT&T have joined in the effort to help remove it by issuing automatic notifications to users that their systems are configured with the rogue DNS network.

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How to detect and fix a machine infected with DNSChanger | MacFixIt - CNET Reviews