You're doing an internal security audit and you want to find out what ports are open on all the servers. What is the best way to find out?

Nmap (Network Mapper) is purpose-built for port scanning and can scan entire subnets or lists of servers simultaneously, reporting open, closed, and filtered ports for each host. It is the most efficient and thorough method for an internal audit of open ports across many servers.

Physically visiting each server provides no direct information about which network ports are open and is completely impractical at scale.

MBSA (Microsoft Baseline Security Analyzer) checks Windows security configurations and missing patches, but is not a port scanner and does not enumerate open TCP/UDP ports.

Manually telneting to every possible port (0-65535) on each server is impractical, error-prone, and does not scale to an audit involving multiple servers.