title: Best OS App for Outbound SMTP Packet Capture?
body: <p>Okay, so this probably sounds terribly nefarious, but I need such capabilities for my senior project. Essentially I'm tasked with writing something that will cut down outbound spam on a zombified pc through a system of packet interception and evaluation. We have a number of algorithms we'll use on the captured messages, but it's the actual capture -- full on interception rather than just sniffing -- that has me a bit stumped.</p>
  
  <p>The app is being designed for windows, so I can't use IP tables. I could use the winpcap libraries, but I don't want to reinvent the wheel if I don't have to. Ettercap seemed a good option, but a test run on vista using the unofficial binaries resulted in nothing but crashes.</p>
  
  <p>So, any suggestions?</p>
  
  <p>Update: Great suggestions. Ended up scaling back the project a bit, but still received an A. I'm thinking Adam Mintz's answer is probably best, though we used WinPcap and Wireshark for the application.</p>