There are many methods that can be used to scan your network for existing vulnerabilities. Some of these mechanisms include:

• Port scanning: A type of scan that determines whether a computer has open TCP or UDP ports. If a port is open on a computer, it means that a network service is running and is listening on that port.
• Network tracing: A scan that attempts to build a network map based on the results returned by the scan.
• Version scanning: The version scan adds to the port scan by attempting to determine which service and what version of that service is running on a given port.
• Network sweeping: This type of scan is used to determine what IP addresses are in use by network connected devices.
• OS fingerprinting: Like version scanning in that the scanner attempts to guess the version of the operating system based on data returned by the scan.