RawCap is a free command line network sniffer for Windows that uses raw sockets.

• Can sniff any interface that has got an IP address, including 127.0.0.1 (localhost/loopback)
• RawCap.exe is just 17 kB
• No external libraries or DLL' s needed other than .NET Framework 2.0
• No installation required, just download RawCap.exe and sniff
• Can sniff most interface types, including WiFi and PPP interfaces
• Minimal memory and CPU load
• Reliable and simple to use