There have been ongoing DDoS attacks against many major carriers and DNS services today. Here are a few articles describing what is going on in case you can't get to certain servers or sites.
As of 6pm EST more attacks are continuing across many data-centers, providers and DNS servers in the USA. Various 3rd party articles below give explination and hour by hour updates on things happening. Rest assured the servers and actual Datacenter network is fine. It is the DNS and upstream data providers having trouble passing all of the requests on their networks.
Level 3 Video Response:
News Article Explanation: