Nfdump 1.6.13 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. The actual developer of this free software for Mac is Peter Haag. The software lies within Internet & Network Tools, more precisely Network tools.
From the developer:
nfdump is a toolset in oder to collect and process netflow and sflow data, sent from netflow/sflow compatible devices. The toolset supports netflow v1, v5/v7, v9, IPFIX and SFLOW. nfdump supports IPv4 as well as IPv6.
nfdump is used as backend toolset for NfSen.
You may want to check out more software for Mac, such as IPNetShareX, PPPoE Connector or tn3270, which might be related to Nfdump.