Derrick is a simple tool for recording data streams of TCP and UDP traffic.
It shares similarities with other network recorders, such as tcpflow and
wireshark, where it is more advanced than the first and clearly inferior to
Derrick has been specifically designed to monitor application-layer
communication. In contrast to other tools the application data is logged in
a line-based ASCII format. Common UNIX tools, such as grep, sed & awk, can
be directly applied. Even replay of recorded communication is straight
forward using netcat.
Derrick supports on-the-fly compression and rotation of log files. The
payloads of TCP sessions are re-assembled using Libnids and can be merged
or truncated. UDP payloads are logged as-is. Details of lower network
layers are omitted.