SiLK (System for Internet-Level Knowledge) consists of two sets of tools: a packing system and an analysis suite. The packing system receives Netflow V5 PDUs or IPFIX and converts them into a more space efficient format, recording the packed records into service-specific binary flat files. The analysis suite consists of tools that can read these flat files and then perform various query operations, ranging from per-record filtering to statistical analysis of groups of records. The analysis tools interoperate using pipes, allowing a user to develop a relatively sophisticated query from a simple beginning.
Yet Another Flowmeter (YAF) is a tool for network flow capture, primarily designed to operate efficiently on white box hardware and generate IPFIX flow records. It is designed to operate primarily on Unix-based systems (including Mac OS X), and is supported by the Network Situational Awareness team at CERT.