Like tcpdump, tcpflow gives you the ability to view the text contents of network packets in real time. Tcpdump, however, is more suited to capturing packets and protocol information. Tcpflow is more suited toward viewing the actual data flow between two hosts. While tcpdump displays output to the console by default, tcpflow writes output to a file by default, and you must use the
-c option if you want to see the tcpflow output on the console.
- Tcpflow is not part of the default pfSense installation. Perhaps the easiest way to install tcpflow is to use the Linux/Unix repositories athttps://pkgs.org: the 64-bit binaries for tcpflow v. 1.5.0 can be found athttps://freebsd.pkgs.org/12/freebsd-ports-latest-amd64/tcpflow-1.5.0.txz.html. Install these into a suitable location on your pfSense system, such as
/usr/sbin/tcpflow. Make sure the binaries are executable; you can do this with the following command: