Captcp is a free and open source program for TCP analysis of PCAP files. Normally recorded via Tcpdump or Wireshark. Captcp is an attempt to rewrite and bundle all common TCP analysis tools in one easy to use program - providing a clean and consistent command line syntax. Captcp is written in Python and easy extendable. Captcp is not a substitute for Tcpdump or Wireshark - it complements these tools instead.