The Network Situational Awareness (NetSA) group at CERT has developed and maintains a suite of open source tools for monitoring large-scale networks using flow data. These tools have grown out of the work of the AirCERT project, the SiLK project and the effort to integrate this work into a unified, standards-compliant flow collection and analysis platform.

CERT is a part of the Software Engineering Institute (SEI), a federally funded research and development center (FFRDC) operated by Carnegie Mellon University.

Featured Projects


The System for Internet Level Knowledge (SiLK) is an efficient network flow collection and storage infrastructure that will accept flow data from a variety of sensors. SiLK also provides a suite of efficient command-line tools for analysis.

YAF 2.8.1

Yet Another Flow Sensor (YAF) processes packet data into bidirectional flow records that can be used as input to an IPFIX Collecting Process. YAF's output can be used with the NetSA Aggregated Flow (NAF) toolchain and the SiLK tools.

Analysis Pipeline 5.3.1

The Analysis Pipeline 5.3 is a streaming analysis tool than can process more than just SiLK flows as done in version 4.x. It can now process YAF records and raw IPFIX records. It can do all of the analyses available in version 4.x. A notable enhancement is expansive DNS record processing. This includes fast flux detection and domain name watchlisting.

super_mediator 1.2.2

super_mediator is an IPFIX mediator for use with the YAF and SiLK tools. It collects and filters YAF output data to various IPFIX collecting processes and/or csv files. super_mediator can be configured to perform de-duplication of DNS resource records as exported by YAF.