__.---,__
   .-`         '-,__
 &/           ',_\ _\
 /               '',_
 |    .            (")
 |__.`'-..--|__|--``   Snifter
      

On Windows, you can't capture on the local loopback address 127.0.0.1 with a packet capture driver like WinPcap - but you can by using a raw socket sniffer, like Snifter.

Additionally, Snifter is a cross-platform, portable tool that doesn't require any drivers to be installed.

Snifter started life as a Windows-only tool, and Linux support was later added just because .NET Core makes it possible.

You must run Snifter with elevated privileges on Windows, or with sudo on Linux - this is an OS-level requirement to create raw sockets.

For now at least, Snifter only supports IPv4. It should be straightforward to add support for IPv6, but I don't use IPv6 yet, so haven't added it.

If you want to capture loopback traffic, it's important that your apps are communicating specifically with 127.0.0.1 - not localhost.

Note that Snifter is restricted to only capturing TCP packets on Linux.

snifter.exe -i x -f filename

  -i, --interface=VALUE      ID of the interface to listen on
  -f, --filename=VALUE       Filename to output sniffed packets to. Defaults to snifter.pcapng
  -o, --operator=VALUE       Whether filters should be AND or OR. Defaults to OR
  -p, --protocol=VALUE       Filter packets by IANA registered protocol number
  -s, --source-address=VALUE Filter packets by source IP address
  -d, --dest-address=VALUE   Filter packets by destination IP address
  -x, --source-port=VALUE    Filter packets by source port number
  -y, --dest-port=VALUE      Filter packets by destination port number
  -h, -?, --help             Show command line options

Run snifter.exe -h to see a list of available network interfaces.

Note that each filter option can only be specified once.