Rawcap can do this. It's increasingly showing its age, but I still use it fairly frequently. It generates PCAP files, it's 23KB, and its only dependency is .NET

Rawcap can do this. It's increasingly showing its age, but I still use it fairly frequently. It generates PCAP files, it's 23KB, and its only dependency is .NET Framework 2.0 (which, admittedly, is becoming more of a problem than a blessing): http://www.netresec.com/?page=RawCap http://www.netresec.com/?page=RawCap