A midsize company has recently begun to experience increased latency and unexpected redirection of web traffic affecting several users. The network administrator suspects a DNS poisoning attack. What initial action should the administrator take to confirm and respond to this suspected security breach?
Change the DNS resolver settings on an affected user's machine to a reputable public DNS server and compare the resolution results.
Clear the DNS cache on the company's primary DNS server to remove any potentially malicious entries.
Install additional DNS servers to handle user requests and prevent overloading a single server that might be causing the issues.
Check for pending software updates for all network devices and user endpoints to ensure they have the latest security patches.