pcapdiff and Detecting Packet Injection and Spoofing

Here is a nice app, and a link to analyzing your traffic for tampering.

pcapdiff

Pcapdiff is a tool developed by the EFF to compare two packet captures and identify potentially forged, dropped, or mangled packets. Two technically-inclined friends can set up packet captures (e.g. tcpdump or Wireshark) on their own computers and produce network traffic between their two computers over the Internet. Later, they can run pcapdiff on the two packet capture files to identify suspicious packets for further investigation. See Detecting packet injection: a guide to observing packet spoofing by ISPs and EFF's Test Your ISP Project for more background.