OS Fingerprinting

OS Fingerprinting, also called TCPIP stack fingerprinting, is the process of determining the identity of a remote operating system by analyzing packets received from that host. There are two types of OS fingerprinting:active and passive. Passive OS fingerprinting identifies the remote operating system by sniffing (capturing) packets exchanged between the source and remote systems. Active OS fingerprinting is the process of sending packets to a host and interpreting the response or lack thereof from that host.