A system administrator is trying to troubleshoot company wide email problems that may be related to DNS. Which of the following network tools would be MOST useful to determine if it is a DNS issue?

netstat displays active network connections, routing tables, and interface statistics, which is not directly used for DNS resolution testing.

tracert (or traceroute) maps the path a packet takes to reach a destination, primarily useful for identifying routing or latency issues, not DNS resolution.

nslookup is a command-line tool specifically designed to query Domain Name System (DNS) servers and resolve hostnames to IP addresses, which is crucial for diagnosing issues where email services cannot locate mail servers by their domain names. It can also be used to query specific record types like MX records, which are essential for email delivery.

ping tests connectivity to an IP address or hostname and measures round-trip time, but it does not provide detailed information about DNS resolution failures themselves, only the resulting inability to reach a host if DNS fails.